Having to step lively can be a nuisance (4)
I believe the answer is:
pest
'a nuisance' is the definition.
(I've seen this in another clue)
'having to step lively can' is the wordplay.
'step' can be anagrammed to 'PEST'.
But, I am unsure how this is indicated.
'be' is the link.
Can you help me to learn more?
(Other definitions for pest that I've seen before include "Aphis" , "Destructive insect or nuisance" , "Destructive creature" , "Troublesome man or animal" , "Annoying person" .)