The most common and most likely answer to this crossword clue is the 5 letter word TOPER
I've seen this crossword clue in The Times
T
O
P
E
R
More clues leading to the result TOPER
- Tips for perfect miso soup side order: lush!
- Drinker reflected about something to smoke
- Lush plant in new container looking up
- Drunk may do this to house plant, if rejected
- Drunkard on marijuana turns up
- Drunk with hat getting very quietly half cut
- Drinker wanting best beer — just half
- Head meets very important lady, one given to drink
- Port and last bit of absinthe drunk — by him?
- On dope? Given up. This fellow prefers alcohol
Buddy explains!

The straight part
We know that "lush" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lush = toper.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.