Think the chaps at the outside are having fun (9)

I believe the answer is:
amusement
'fun' is the definition.
(amusement is fun or enjoyment)
'think the chaps at the outside' is the wordplay.
'think' becomes 'muse' (to muse on something is to think about it).
'the chaps' becomes 'men' (chap can mean a man).
'the outside' is an insertion indicator (some letters go outside others).
'muse'+'men'='musemen'
'musemen' put inside 'at' is 'AMUSEMENT'.
'are having' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for amusement that I've seen before include "Pastime; recreation" , "enjoyment for 19 > [(type of) PARK]" , "Diversion, recreation" , "Pleasure, diversion" , "Entertainment" .)
