Discomfit seaman Wood (5)
I believe the answer is:
abash
'discomfit' is the definition.
(abashing is a kind of discomfiting)
'seaman wood' is the wordplay.
'seaman' becomes 'ab' (short for able seaman).
'wood' becomes 'ash' (wood from an ash tree).
'ab'+'ash'='ABASH'
(Other definitions for abash that I've seen before include "Cause to feel 4" , "Crush" , "Cause embarrassment" , "show up" , "Embarrass" .)