The most common and most likely answer to this crossword clue is the 7 letter word URETHRA
I've seen this crossword clue in Financial Times
U
R
E
T
H
R
A
More clues leading to the result URETHRA
- University, rather unorthodox, that’s used by a peer
- Passing water duct in old city with churned earth
- Arthur managed to cover end of one waste pipe
- Arthur, drunk, catching Edgware’s last Tube
- Piss-taker – in future, thrash!
- Type of bend on rather flexible duct
- You’re thrashed? To an extent one has to go through it
Buddy explains!
The straight part
We know that "waste pipe" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case waste pipe = urethra.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.
What does URETHRA mean?
URETHRA noun- The tube through which urine exits the body and, in penises, through which semen is ejaculated.