Ride waves and regularly resist excess (7)
I believe the answer is:
surfeit
'excess' is the definition.
(synonyms)
'ride waves and regularly resist' is the wordplay.
'ride waves' becomes 'surf' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'and' says to put letters next to each other.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternate letters of 'resist' are 'eit'.
'surf'+'eit'='SURFEIT'
Can you help me to learn more?
(Other definitions for surfeit that I've seen before include "Superabundance" , "stuff, once" , "Fustier (anag)" , "Overindulge" , "it's more than one needs" .)