Pass by and see moving round inside (6)
I believe the answer is:
elapse
'pass by' is the definition.
(thesaurus)
'see moving round inside' is the wordplay.
'moving' is an anagram indicator.
'round' becomes 'lap' (as in a round or lap of a park**).
'inside' means one lot of letters goes inside another.
'see' with letters rearranged gives 'ese'.
'ese' going around 'lap' is 'ELAPSE'.
'and' acts as a link.
(Other definitions for elapse that I've seen before include "pass in silence" , "Pass away - asleep (anag)" , "Go by - pass away" , "Passing" , "(Of time) go by" .)