Like bog Bill is on (6)
I believe the answer is:
admire
'like' is the definition.
(I've seen this in another clue)
'bog bill is on' is the wordplay.
'bog' becomes 'mire' (mire is a kind of bog).
'bill' becomes 'ad' (advertisement stuck on wall).
'is on' is a charade indicator (letters next to each other).
'mire' after 'ad' is 'ADMIRE'.
(Other definitions for admire that I've seen before include "Respect (someone)" , "Respect and approve of" , "Goggle at" , "Hold in high respect" , "Revere" .)