Swells are contracted to wear fashionable suits? (9)
I believe the answer is:
increases
'swells are contracted to wear' is the definition.
I can't tell whether this definition defines the answer.
'fashionable suits?' is the wordplay.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'suits?' becomes 'creases' (I can't justify this - if you can you should give a lot more credence to this answer).
'in'+'creases'='INCREASES'
Can you help me to learn more?
(Other definitions for increases that I've seen before include "Gets bigger" , "Becomes greater" , "Becomes bigger" .)