Son needs taxi? He won’t come out (4)
I believe the answer is:
scab
'he won't come out' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'son needs taxi?' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'needs' says to put letters next to each other.
'taxi?' becomes 'cab' ('cab' can be a synonym of 'taxi').
's'+'cab'='SCAB'
Can you help me to learn more?
(Other definitions for scab that I've seen before include "Encrustation for the strikebreaker" , "sign of wound healing" , "Blackleg (colloq.)" , "Sore - blackleg" , "Blackleg, strike-breaker" .)