Punish sailor, also spreading the fear (3,3,7)
I believe the answer is:
tar and feather
'punish' is the definition.
(I know that tar-and-feather is a type of punish)
'sailor also spreading the fear' is the wordplay.
'sailor' becomes 'tar' (slang term for a sailor).
'also' becomes 'and' (both can mean in addition).
'spreading' indicates anagramming the letters.
'the'+'fear'='thefear'
'thefear' with letters rearranged gives 'feather'.
'tar'+'and'+'feather'='TAR-AND-FEATHER'
(Other definitions for tar and feather that I've seen before include "Unofficially punish" , "Punish with humiliating coverings" .)