Maybe Stubbs composition of fair day is daring (8)
I believe the answer is:
unafraid
'is daring' is the definition.
(I've seen this before)
'maybe stubbs composition of fair day' is the wordplay.
'maybe stubbs' becomes 'Una' (actress Una Stubbs is an example).
'composition of' is an anagram indicator (I've seen this in other clues).
'day' becomes 'd' (abbreviation for day).
'fair' with letters rearranged gives 'frai'.
'una'+'frai'+'d'='UNAFRAID'
(Other definitions for unafraid that I've seen before include "Intrepid" , "Not scared or intimidated" , "Not scared or apprehensive" , "Not frightened" , "Not fearful or scared" .)