Brave senior follows bee noise (4)
I believe the answer is:
bold
'brave' is the definition.
(similar in meaning)
'senior follows bee noise' is the wordplay.
'senior' becomes 'old' (similar in meaning).
'follows' is a charade indicator (letters next to each other).
'noise' indicates a 'sounds like' (homophone) clue.
'bee' sounds like 'b'.
'old' put after 'b' is 'BOLD'.
(Other definitions for bold that I've seen before include "Prominent" , "Daring, maybe impudent" , "Suspended; kept cold" , "Typeface with thick heavy lines" , "Audacious" .)