It comes early for one being sent off (4)
I believe the answer is:
bath
'it comes early for one being sent off' is the definition.
The definition suggests a singular noun which matches the answer.
'it' is the wordplay.
I cannot quite see how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
The remaining letters 'bah' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
(Other definitions for bath that I've seen before include "SW spa city" , "where one may pull the plug on a singer" , "Tub for washing" , "Georgian city" , "Large washtub - English city" .)