Forgive sailor taking crack (7)
I believe the answer is:
absolve
'forgive' is the definition.
(I know that absolve is a more specific form of the action forgive)
'sailor taking crack' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'taking' says to put letters next to each other.
'crack' becomes 'solve' (crack can mean to solve or decipher).
'ab'+'solve'='ABSOLVE'
(Other definitions for absolve that I've seen before include "Exculpate" , "Set free from guilt" , "Free (a person) from guilt" , "Lob vase (anag.)" , "Let off the hook" .)