Club acquired keeps American making a buck (5,4)

'a buck' is the definition.
(thesaurus)

'club acquired keeps american' is the wordplay.
'club' becomes 'billy' (billy is a kind of club**).
'acquired' becomes 'got' ('get' can be a synonym of 'acquire').
'keeps' indicates putting letters inside.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'got' going around 'a' is 'goat'.
'billy'+'goat'='BILLY-GOAT'

'making' is the link.