Flamboyant jumper worn by company Charlie (6)
I believe the answer is:
rococo
'flamboyant' is the definition.
(thesaurus)
'jumper worn by company charlie' is the wordplay.
'jumper' becomes 'roo' (I've seen this before).
'worn by' indicates putting letters inside (I've seen this in other clues).
'company' becomes 'co' (abbreviation).
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'co'+'c'='coc'
'roo' going around 'coc' is 'ROCOCO'.
(Other definitions for rococo that I've seen before include "Elaborately ornate" , "Late baroque style (of furniture or architecture)" , "fine style" , "Ornate style of decoration." , "Florid style" .)