Dance beat, good one at first (5)
I believe the answer is:
tango
'dance' is the definition.
(Tango is a dance)
'beat good one at first' is the wordplay.
'beat' becomes 'tan' (tan can mean to beat or hit).
'good' becomes 'g' (abbreviation).
'one at first' becomes 'o' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tan'+'g'+'o'='TANGO'
Can you help me to learn more?
(Other definitions for tango that I've seen before include "Rhythmic movement" , "Dance; letter T" , "South American dance (for two?)" , "Argentinian dance form" , "One from Argentina" .)