Speed last of dinner gets consumed (4)
I believe the answer is:
rate
'speed' is the definition.
(rate is a kind of speed)
'last of dinner gets consumed' is the wordplay.
'last of' indicates one should take the final letters.
'gets' means one lot of letters go next to another.
'consumed' becomes 'ate' (eating is a kind of consuming).
The final letter of 'dinner' is 'r'.
'r'+'ate'='RATE'
(Other definitions for rate that I've seen before include "Be worthy of; speed" , "Estimate value of - speed" , "Price - class - speed" , "Assess; be worthy of" , "Deserve; scold" .)