Humiliated by answer when caught in bed (6)
I believe the answer is:
abased
'humiliated' is the definition.
('abase' can be a synonym of 'humiliate')
'answer when caught in bed' is the wordplay.
'answer' becomes 'a' (abbreviation eg in Q and A).
'when' becomes 'as'.
'caught in' means one lot of letters goes inside another.
'as' inserted into 'bed' is 'based'.
'a'+'based'='ABASED'
'by' is the link.
(Other definitions for abased that I've seen before include "Degraded, humbled" , "Humiliated or degraded" , "Demeaned (oneself)" , "Belittled, degraded" , "Put down" .)