Reportedly compare tiny organisms (6)
I believe the answer is:
lichen
'tiny organisms' is the definition.
Although both the answer and 'organisms' are nouns, they are not in the same form of the noun.
'reportedly compare' is the wordplay.
'reportedly' shows a homophone (sound like).
'compare' becomes 'liken' (synonyms).
'liken' is a homophone of 'LICHEN'.
Can you help me to learn more?
(Other definitions for lichen that I've seen before include "Growth found on tree trunks and rocks" , "Tiny plants found on rocks, tree-trunks etc" , "Tiny plants found on rocks and trees" , "Tiny plants growing on rocks and treetrunks" , "Small plants found on tree-trunks and stones" .)