Girl has nasty time with love restricted (6)
I believe the answer is:
violet
'girl' is the definition.
'nasty time with love restricted' is the wordplay.
'nasty' becomes 'vile' (synonyms).
'time' becomes 't' (abbreviation).
'with' is a charade indicator (letters next to each other).
'love' becomes 'o' (love means zero in tennis).
'restricted' indicates putting letters inside.
'vile'+'t'='vilet'
'vilet' placed around 'o' is 'VIOLET'.
'has' is the link.
(Other definitions for violet that I've seen before include "Rainbow colour; flower" , "Shade of purple" , "A flower for a girl" , "Flower-girl" , "Five-petalled flower" .)