Another name for a sail, perhaps (5)
I believe the answer is:
alias
'another name' is the definition.
(I've seen this before)
'a sail perhaps' is the wordplay.
'perhaps' is an anagram indicator.
'sail' anagrammed gives 'lias'.
'a'+'lias'='ALIAS'
'for' is the link.
(Other definitions for alias that I've seen before include "Alternative name" , "False or assumed name" , "Handle that isn't genuine" , "Otherwise - an assumed name" , "stage name, perhaps" .)