Call some prison guards (4)
I believe the answer is:
song
'call' is the definition.
(synonyms)
'some prison guards' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'SONG' can be found hidden inside 'prison guards'.
(Other definitions for song that I've seen before include "Piece of music, usually with words" , "Musical number" , "Lied" , "Vocal item" , "See 17" .)