Stay away from child sent to bed on time (7)
I believe the answer is:
boycott
'stay away from' is the definition.
(I've seen this in another clue)
'child sent to bed on time' is the wordplay.
'child' becomes 'boy' (synonyms).
'sent to' says to put letters next to each other.
'bed' becomes 'cot' (cot is a type of bed).
'on' is a charade indicator (letters next to each other).
'time' becomes 't' (abbreviation).
'boy'+'cot'+'t'='BOYCOTT'
(Other definitions for boycott that I've seen before include "ex-Yorkshire cricket captain" , "Refuse to do business with" , "Refuse to trade with" , "Trade embargo" , "Refuse to deal with - outlaw" .)