Long to swap husband for new recruit (4)
I believe the answer is:
sign
'recruit' is the definition.
(I've seen this in other clues)
'long to swap husband for new' is the wordplay.
I cannot quite see how this works, but
'new' could be 'n' (common abbreviation eg NT for New Testament) and 'n' is located in the answer.
The remaining letters 'sig' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sign that I've seen before include "As the star was for 14 across" , "Authorise with a name" , "Communicate silently" , "Leo, for instance" , "Indicator" .)