Now line up (8)
I believe the answer is:
increase
'up' is the definition.
(I've seen this before)
'now line' is the wordplay.
I cannot really understand how this works, but
'line' could be 'crease' (synonyms) and 'crease' is found in the answer.
The remaining letters 'in' 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 increase that I've seen before include "Become bigger or greater in amount" , "Augment or enlarge (8)." , "'Augment, expand (8)'" , "Profit" , "Become greater in size" .)