Economize with second wave (6)
I believe the answer is:
scrimp
'economize' is the definition.
(I've seen this in another clue)
'second wave' is the wordplay.
'second' becomes 's' (common abbreviation).
'wave' becomes 'crimp' (crimping is a kind of waving).
's'+'crimp'='SCRIMP'
'with' acts as a link.
(Other definitions for scrimp that I've seen before include "Treat stingily" , "Be economical and sparing" , "make economies" , "Be frugal and sparing" , "Economise, be thrifty" .)