Ring a girl at the weekend (5)
I believe the answer is:
knell
'ring' is the definition.
(synonyms)
'a girl at the weekend' is the wordplay.
'a girl' becomes 'Nell' (girl's name).
'at' means one lot of letters go next to another (I've seen this in other clues).
'the weekend' becomes 'k' (I've seen this in other clues).
'nell' put after 'k' is 'KNELL'.
(Other definitions for knell that I've seen before include "''The curfew tolls the ... of parting day'' (Thomas Gray)" , "Toll (bell)" , "Toll, ring" , "Sound of funeral bell" , "it precipitates death" .)