Another increase? (5)
I believe the answer is:
again
'another' is the definition.
(I've seen this before)
'increase?' is the wordplay.
I cannot quite see how this works, but
'increase?' could be 'gain' (gaining is a kind of increasing) and 'gain' is present in the answer.
A single letter 'a' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for again that I've seen before include "Next time" , "Anew" , "One more time, encore" , "second term" , "repeat order" .)