Other words derived ultimately from Lat. quătĕre
Lat. concŭtĕre was derived by means of the prefix con‑ which meant ‘with, together’, but which could also be used as an intensive prefix. The meaning of this word was ‘to shake together’ (together con‑) or ‘to shake violently’ (intensive con‑). In addition, this verb had other figurative meanings, such as ‘to put in fear, terror, or anxiety, to terrify, alarm, trouble’ (L&S).
When English borrowed this Latin verb, as concuss [kənˈkʰʌs], it borrowed the participial form of this verb, concŭssus, but without the inflectional ending ‑us (con+cŭssus; stem: concŭss‑, inflection ‑us). When it was first borrowed, in the late 16th century, it had the meaning ‘to shake violently; to agitate, disturb. Chiefly figurative’ (OED). By and large, the meaning of this verb since the late 17th century has been ‘to injure (the brain, etc.) by concussion’ (OED). In other words, the verb’s meaning is defined in terms of the noun concussion, which is much more common (see below).
The verb concuss is typically used in the passive, with the participle concussed, as in He was concussed by the blast (LDCE). A few major English dictionaries mention other senses for concuss, which are quite rare, such as a sense that goes back to the original one: ‘to shake violently; to agitate, disturb’, a sense that is used mostly figuratively (OED). Another sense that some dictionaries mention is ‘to force or influence by intimidation : coerce’ (WNTIUD), which SOED tells us that it is an archaic meaning found primarily in Scotland. Spanish does not have a descendant of the Latin verb concŭtĕre, for it was neither passed on patrimonially nor was it borrowed from written Latin at a later date.
As we just said, the English verb concuss is rare and much less common than the noun associated with it, namely concussion [kənˈkʰʌʃən]. This noun was borrowed from Latin concŭssĭōn‑, the action noun derived from the verb concŭtĕre, formed in Latin from the passive participle stem concŭss‑ of the verb plus the noun-forming suffix ‑ĭōn‑ (con‑cŭss‑ĭōn‑, nominative wordform: concŭssĭō, accusative wordform: concŭssĭōnem). Actually, the noun concussion was borrowed much earlier than the verb concuss, in the early 15th century. This Latin noun meant primarily ‘a shaking, an act of shaking’, though it had a secondary meaning in jurisprudence, namely ‘an extortion of money by means of threats’ (L&S). Note that in American English slang, the phrasal verb to shake down means ‘to extort money from someone’ and the noun shakedown (or shake-down) means ‘extortion of money, as by blackmail’ (AHD; also ‘a thorough search of a place or person’).
The main meaning of the noun concussion in Modern English is ‘temporary unconsciousness or confusion caused by a blow on the head’ (COED) or ‘an injury to the brain that is caused by something hitting the head very hard’ (Merriam-Webster's Advanced Learner's Dictionary). Some dictionaries describe a concussion in terms of injury or brain damage, whereas others do not. Many dictionaries mention that the condition is temporary, though not all of them do, e.g. ‘temporary damage to the brain…’ (Cambridge Advanced Learners Dictionary). Some dictionaries mention that the noun concussion is a count noun in American English, as in She suffered a severe concussion after falling on the ice, whereas it is a mass noun in British English, as in He went to hospital with concussion (MWALD).
The primary way to express the medical sense of Eng. concussion in Spanish is conmoción cerebral, which literally translates as brain commotion, and, for the less common ‘shaking’ sense of Eng. concussion, sacudida, a noun derived by conversion from the past participle of the verb sacudir ‘to shake’. (Spanish-English dictionaries translate sacudida as shake, jolt, jerk, earthquake, and shock.) At least one of the major English-Spanish dictionaries gives us the word concusión as an alternative to conmoción cerebral to translate Eng. concussion, namely the Oxford English-Spanish Dictionary (OSD), but this is not the way this word is normally used in Spanish (other than perhaps in areas with heavy influence from the English language).
The word concusión exists in Spanish, though it is rare and technical and it means something different from what its English cognate means. The meaning of Sp. concusión derives from the secondary meaning its source had in legal Latin, namely ‘collection of a fine or a tax, made by an official for his own benefit’ (Clave). María Moliner’s is the only major Spanish dictionary that tells us that concusión has been used in medicine with the meaning ‘violent blow, especially on the head’ (MM), but that use of concusión did not catch on and it is now obsolete.
Sp. concusión is attested in the late 16th century (1580, DCEH). Its French cognate concussion is attested some forty years earlier with the legal meaning and much earlier, in the early 14th century, with the now obsolete sense ‘shock, jerk, jolt’ (Le Grand Robert). This makes us wonder whether whereas the Oxford English Dictionary tells us that English borrowed the noun concussion directly from Latin (c. 1400), it might not be possible that the existence of the French cognate was the inspiration for this loanword. However, clearly when French concussion changed its meaning from the primary one it had had in Latin to the secondary legal one, English concussion did not follow suit.
Now that we know how to translate concussion into Spanish we might wonder how to translate the English verb concuss. This verb or, rather, its much more common passive form, to be concussed, translates as sufrir una conmoción cerebral. Some English-Spanish dictionaries mention that the rare, figurative sense of concuss mentioned above translates as conmocionar (e.g. Harrap’s, GU), but this is a very rare use of Eng. concuss.
 The original says: ‘Cobro de una multa o de un impuesto, hecho por un funcionario en su propio provecho’ (Clave). The DLE has as the single meaning for this word: ‘Exacción arbitraria hecha por un funcionario público en provecho propio’ (DLE).
 The original says: ‘(ant.) Med. *Golpe violento, especialmente en la cabeza’ (MM).