Almost share in public function (9)
I believe the answer is:
operation
'function' is the definition.
(thesaurus)
'almost share in public' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'share' becomes 'ration' (ration is a kind of share).
'in' indicates putting letters inside.
'public' becomes 'open' ('open' can be similar in meaning to 'public').
'ration' with its final letter removed is 'ratio'.
'ratio' going within 'open' is 'OPERATION'.
(Other definitions for operation that I've seen before include "Act of surgery" , "activity" , "Action; process" , "Surgical or military procedure" , "Manoeuvre - military action" .)