Choose rice: endlessly exciting (8)
I believe the answer is:
electric
'exciting' is the definition.
(similar in meaning)
'choose rice endlessly' is the wordplay.
'choose' becomes 'elect' (electing is a kind of choosing).
'endlessly' means to remove the last letter.
'rice' with its last letter removed is 'ric'.
'elect'+'ric'='ELECTRIC'
(Other definitions for electric that I've seen before include "sort of guitar?" , "Highly charged" , "Energetic" , "Thrillingly exciting" , "Form of energy for lighting" .)