Extra upsetting to a lady (5)
I believe the answer is:
other
'extra' is the definition.
(I've seen this in another clue)
'upsetting to a lady' is the wordplay.
'upsetting' says the letters should be written in reverse.
'a lady' becomes 'her' (her refers to a woman).
'to' in reverse letter order is 'ot'.
'ot'+'her'='OTHER'
(Other definitions for other that I've seen before include "Distinct" , "Throe (anag)" , "Alternative - unrelated" , "Different, alternative" , "Different (from those mentioned)" .)