Firm ground flour a little unevenly and left rich (9)
I believe the answer is:
colourful
'rich' is the definition.
(similar in meaning)
'firm ground flour a little unevenly and left' is the wordplay.
'firm' becomes 'co' (a firm is a company).
'ground' indicates anagramming the letters ('grind' the letters into a new form).
'a little' indicates taking the first letters.
'and' is a charade indicator (letters next to each other).
'left' becomes 'l' (common abbreviation).
The initial letter of 'unevenly' is 'u'.
'flour' is an anagram of 'lourf'.
'co'+'lourf'+'u'+'l'='COLOURFUL'
(Other definitions for colourful that I've seen before include "Lively, exciting" , "Having striking hues" , "Vivid and distinctive" , "Containing lots of swear-words (of language)" .)