Too apparent in allusion here and there? (4)
I believe the answer is:
also
'too' is the definition.
(synonyms)
'allusion here and there?' is the wordplay.
'here and there?' means one should take alternating letters (here and then can mean regularly).
The alternate letters of 'allusion' are 'ALSO'.
'apparent in' is the link.
(Other definitions for also that I've seen before include "As well, in addition" , "What's more" , "item's rarely used now for this" , "in accompaniment" , "Likewise" .)