Sailor has time for cake (4)
I believe the answer is:
tart
'time for cake' is the definition.
(I know that cake different from tart)
'sailor has' is the wordplay.
'sailor' becomes 'tar' (tar can mean a sailor).
'has' becomes 't' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tar'+'t'='TART'
Can you help me to learn more?
(Other definitions for tart that I've seen before include "Sour-tasting pie?" , "Flat pie" , "Open-topped pie" , "Sharp; pastry" , "Bitter - sweet - floozie" .)