Trouble in Ismailia (3)
I believe the answer is:
ail
'trouble' is the definition.
(synonyms)
'in ismailia' is the wordplay.
'in' indicates a hidden word.
'AIL' is hidden within 'ismailia'.
(Other definitions for ail that I've seen before include "distress" , "upset" , "Be unwell, suffer" , "Be in poor health" , "Be ill or unwell" .)