Chipmunk back to irk exterminator? (5)
I believe the answer is:
dalek
'chipmunk back to irk exterminator?' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'chipmunk back to irk exterminator?' is the wordplay.
'back' suggests the final letters (the letter at the back).
'to' means one lot of letters go next to another (I've seen this in other clues).
'irk exterminator?' becomes 'dale' (I am not sure about this - if you are sure you should believe this answer much more).
The last letter of 'chipmunk' is 'k'.
'k' put after 'dale' is 'DALEK'.
Can you help me to learn more?
(Other definitions for dalek that I've seen before include "Croaky-voiced exterminator" , "Hostile alien" , "Alien creature" , "Doctor Who creature" , "Robot with staccato voice" .)