Sailor, Mark, to go without (7)
I believe the answer is:
abstain
'go without' is the definition.
(I've seen this before)
'sailor mark' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'mark' becomes 'stain' (synonyms).
'ab'+'stain'='ABSTAIN'
'to' is the link.
(Other definitions for abstain that I've seen before include "Cut it out!" , "Take no part" , "Do without, as in lent" , "Go without" , "Refuse to vote" .)