House with tailless mice? That's funny! (5)
I believe the answer is:
comic
'funny' is the definition.
(comic can mean funny or humorous)
'house with tailless mice?' is the wordplay.
'house with' becomes 'co' (I can't explain this - if you can you should give a lot more credence to this answer).
'tailless' means to remove the last letter (the tail of the word is removed).
'mice' with its final letter removed is 'mic'.
'co'+'mic'='COMIC'
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for comic that I've seen before include "Funny entertainer, often stand-up" , "Funny, ridiculous" , "Funny man, maybe stand-up" , "Stand-up possibly" , "Raising a laugh" .)