Hoskins had to enter contest? That's clear! (7)
I believe the answer is:
evident
'clear' is the definition.
(synonyms)
'hoskins had to enter contest?' is the wordplay.
'hoskins had' becomes 'I'd' (where the crossword setter is 'Hoskins').
'to enter' means one lot of letters goes inside another.
'contest?' becomes 'event' (event can mean a sporting competition).
'id' put within 'event' is 'EVIDENT'.
'that's' acts as a link.
(Other definitions for evident that I've seen before include "Obvious - 1 across" , "Clearly discernible" , "Obvious, quite apparent" , "Readily apparent" , "Quite obvious, manifest" .)