Striking may help one man out (10)
I believe the answer is:
phenomenal
'striking' is the definition.
(thesaurus)
'help one man out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'help'+'one'+'man'='helponeman'
'helponeman' anagrammed gives 'PHENOMENAL'.
'may' is the link.
(Other definitions for phenomenal that I've seen before include "Unusual" , "Amazing" , "Exceptionally good" , "Mind-blowing" , "Extraordinary - help one man (anag)" .)