Hope, former film star, mostly thanks to clubs in New York (10)
I believe the answer is:
expectancy
'hope' is the definition.
(thesaurus)
'former film star mostly thanks to clubs in new york' is the wordplay.
I cannot quite see how this works, but
'former' could be 'ex' (prefix meaning former or onetime) and 'ex' is found within the answer.
'thanks' could be 'ta' (UK informal version of 'thank you') and 'ta' is located in the answer.
'clubs' could be 'c' (abbreviation used in card games such as bridge) and 'c' is found within the answer.
'new' could be 'n' (common abbreviation eg NT for New Testament) and 'n' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for expectancy that I've seen before include "Anticipation" , "See 21" .)