Extremely drunk drinking drink, one avoids stairs (5)
I believe the answer is:
dalek
'one avoids stairs' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'extremely drunk drinking drink' is the wordplay.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'drinking' means one lot of letters goes inside another (inserted letters are consumed or drunk).
'drink' becomes 'ale' (type of beer).
'drunk' with its middle removed is 'dk'.
'dk' placed around 'ale' is 'DALEK'.
Can you help me to learn more?
(Other definitions for dalek that I've seen before include "Talking robot" , "SF villain" , "Robot with staccato voice" , "Alien creature" , "Alien creation" .)