Floods one sister with appointments (9)

I believe the answer is:

inundates

'floods' is the definition.
('inundate' can be a synonym of 'flood')

'one sister with appointments' is the wordplay.
'one' becomes 'i' (Roman numeral).
'sister' becomes 'nun' (I've seen this before).
'with' means one lot of letters go next to another.
'appointments' becomes 'dates' ('date' can be a synonym of 'appointment').
'i'+'nun'+'dates'='INUNDATES'

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

I've seen this clue in The Telegraph.

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