Sort of horse for amateur activity (5)
I believe the answer is:
hobby
This might be a double definition.
'sort of horse' is the first definition.
'hobby' can be an answer for 'horse'. I'm not certain of the 'sort of' bit.
'amateur activity' is the second definition.
'hobby' can be an answer for 'activity' (hobby is a kind of activity). I'm not certain of the 'amateur' bit.
'for' is the link.
Can you help me to learn more?
(Other definitions for hobby that I've seen before include "Small falcon" , "Bird of prey - pastime" , "Raptor - pastime" , "activity giving pleasure" , "pursuit of birdwatcher?" .)