Swamps single sister with boyfriends? (9)

I believe the answer is:

inundates

'swamps' is the definition.
('inundate' can be a synonym of 'swamp')

'single sister with boyfriends?' is the wordplay.
'single' becomes 'I' (one).
'sister' becomes 'nun' (sister is a term of address for a nun).
'with' means one lot of letters go next to another.
'boyfriends?' becomes 'dates' (date can mean someone you are dating).
'i'+'nun'+'dates'='INUNDATES'

(Another definition for inundates that I've seen is " Floods".)

I've seen this clue in The Telegraph.

Want a hint initially instead of a full solution? Install my app