Transform mania into liveliness (9)
I believe the answer is:
animation
'liveliness' is the definition.
(synonyms)
'transform mania into' is the wordplay.
'transform' indicates anagramming the letters.
'mania'+'into'='maniainto'
'maniainto' anagrammed gives 'ANIMATION'.
(Other definitions for animation that I've seen before include "Liveliness and enthusiasm" , "Liveliness - illusion of movement in cartoon films" , "Making of cartoons" , "Being full of energy" , "Film technique; lively state" .)