Disturbing one in Gents put out (9)
I believe the answer is:
upsetting
'disturbing' is the definition.
(synonyms)
'one in gents put out' is the wordplay.
'one' becomes 'i' (Roman numeral).
'in' indicates putting letters inside.
'out' indicates an anagram (out can mean wrong or inaccurate).
'gents'+'put'='gentsput'
'gentsput' with letters rearranged gives 'upsettng'.
'i' put within 'upsettng' is 'UPSETTING'.
(Other definitions for upsetting that I've seen before include "sad?" , "Tipping" , "Distressing" , "Likely to put out" , "worrying" .)