Mike in unresponsive state? Just a short break (5)
I believe the answer is:
comma
'a short break' is the definition.
(I have seen 'Short break' mean 'comma' so perhaps 'break' could also mean 'comma'; 'short' indicates an abbreviation)
'mike in unresponsive state?' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'in' indicates putting letters inside.
'unresponsive state?' becomes 'coma' (a coma is an unconscious state).
'm' inserted inside 'coma' is 'COMMA'.
'just' acts as a link.
(Other definitions for comma that I've seen before include "Short break" , "Clause-separating punctuation" , "I signal a break" , "breathtaking marking?" , "Punctuation mark - butterfly" .)