Sweetheart of sailor appearing in Times (4)
I believe the answer is:
baby
'sweetheart' is the definition.
(both are terms of endearment)
'sailor appearing in times' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'appearing in' is an insertion indicator.
'times' becomes 'by' (both can mean 'multiplied by').
'ab' going into 'by' is 'BABY'.
'of' is the link.
(Other definitions for baby that I've seen before include "Timid person; very small" , "Lumbered, left holding this" , "about to howl?" , "Pamper; childish person" , "New-born child" .)