Settle for salary increase? (3,2)
I believe the answer is:
pay up
'settle' is the definition.
(I know that pay is a is a more specific form of the action of pay up)
'salary increase?' is the wordplay.
'salary' becomes 'pay' (synonyms).
'increase?' becomes 'up' (upping is a kind of increasing).
'pay'+'up'='PAY UP'
'for' is the link.
(Other definitions for pay up that I've seen before include "Hand over the money" , "Discharge a debt" , "Give me the money!" , "Settle" .)