Sailor meets girl at port? That's unusual! (8)
I believe the answer is:
abnormal
'unusual' is the definition.
(I've seen this before)
'sailor meets girl at port?' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'meets' means one lot of letters go next to another.
'girl' becomes 'norma' (**).
'at' means one lot of letters go next to another.
'port?' becomes 'l'.
'ab'+'norma'+'l'='ABNORMAL'
'that's' is the link.
(Other definitions for abnormal that I've seen before include "Deviating from the standard" , "Rum" , "Irregular" , "Odd" , "like 15 [ANOMALIES]" .)