Love on flipping stormy night (7)
I believe the answer is:
nothing
'love' is the definition.
(love means zero in tennis)
'on flipping stormy night' is the wordplay.
'flipping' shows that the letters should be reversed in order.
'stormy' indicates an anagram (stormy suggests disruption).
'on' back-to-front is 'no'.
'night' anagrammed gives 'thing'.
'no'+'thing'='NOTHING'
(Other definitions for nothing that I've seen before include "'Zero, zilch (7)'" , "Naught, nil, nix" , "Item of no importance" , "Naught, nowt, zilch" , "See 13" .)