Appear to observe many (4)
I believe the answer is:
seem
'appear' is the definition.
('seem' can be a synonym of 'appear')
'observe many' is the wordplay.
'observe' becomes 'see' (I've seen this before).
'many' becomes 'm' (**).
'see'+'m'='SEEM'
'to' is the link.
(Other definitions for seem that I've seen before include "Appear, look" , "Come across as" , "Appear, give impression of being" , "Appear to the eye" .)