Dance with an enthusiast, a boy with energy (8)
I believe the answer is:
fandango
'dance' is the definition.
(fandango is a kind of dance)
'with an enthusiast a boy with energy' is the wordplay.
'with' means one lot of letters go next to another.
'an enthusiast' becomes 'fan' (fan is a kind of enthusiast).
'a boy with' becomes 'dan' (I can't justify this - if you can you should give a lot more credence to this answer).
'energy' becomes 'go' (I've seen this in other clues).
'fan' put next to 'dan' is 'fandan'.
'fandan'+'go'='FANDANGO'
Can you help me to learn more?
(Other definitions for fandango that I've seen before include "Lively Spanish dance" , "Old Spanish dance in triple time" , "Old Spanish dance, with castanets" , "Spanish dance -- a dong fan (anag)" , "Spanish 2 Down" .)