Male trapped in small ravine twitches (6)
I believe the answer is:
spasms
'twitches' is the definition.
(I've seen this in another clue)
'male trapped in small ravine' is the wordplay.
'male' becomes 'm' (common abbreviation).
'trapped in' indicates putting letters inside.
'small' becomes 's' (abbreviation - e.g. clothes size).
'ravine' becomes 'pass' (pass can mean a ravine).
's'+'pass'='spass'
'm' placed into 'spass' is 'SPASMS'.
(Other definitions for spasms that I've seen before include "Convulsions or cramps" , "Sudden muscular contractions" , "spells" , "Sudden convulsions" , "Convulsions, fits" .)