Veteran's former wife in the chair (3,5)
I believe the answer is:
old sweat
'veteran's' is the definition.
I know nothing about this answer so I can't tell whether this works.
'former wife in the chair' is the wordplay.
'former' becomes 'old' (both can mean previous).
'wife' becomes 'w'.
'in the' means one lot of letters goes inside another.
'chair' becomes 'seat' (something to sit on).
'w' put within 'seat' is 'sweat'.
'old'+'sweat'='OLD SWEAT'
Can you help me to learn more?
(Other definitions for old sweat that I've seen before include "Veteran soldier" , "Veteran, one expected to 7" , "Very experienced chap" .)