Increase the rate (10)
But I've got no explanation for this one! Could you help me understand?
(Other definitions for accelerate that I've seen before include "Crank up" , "Quicken" , "snowball" , "Increase speed" , "Go faster" .)
'increase the rate' is the definition.
The answer and definition are not the same part of speech.
'increase the rate' is the wordplay.
I cannot really see how this works, but
'increase' could be 'up' (upping is a kind of increasing) and 'up' is located in the answer.
'rate' could be 'speed' (speed is a kind of rate) and 'speed' is found within the answer.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for speed up that I've seen before include "career" , "put foot down" , "Get faster" , "Work faster" , "go faster!" .)