Aggressive and popular solver’s champion, keeping fine (2-4-4)
I believe the answer is:
in-your-face
'aggressive' is the definition.
(I've seen this in another clue)
'popular solver's champion keeping fine' is the wordplay.
'popular' becomes 'in' ('in' can mean trendy).
'solver's' becomes 'your' (belonging to you the crossword solver).
'champion' becomes 'ace' (both can mean a person excelling at something).
'keeping' is an insertion indicator (some letters kept inside).
'fine' becomes 'f' (abbreviation in pencil classifications).
'your'+'ace'='yourace'
'yourace' going around 'f' is 'yourface'.
'in'+'yourface'='IN-YOUR-FACE'
'and' is the link.
(Other definitions for in-your-face that I've seen before include "Impossible to ignore or avoid" , "Blatantly aggressive" , "Blatantly provocative" .)