Cryptic crossword clue
One hesitates to revive English leader after knockout 12

The most common and most likely answer to this crossword clue is the 12 letter word ANAESTHETISE

I've seen this crossword clue in The Guardian
A
N
A
E
S
T
H
E
T
I
S
E

Buddy explains!

The straight part
We know that "knockout" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case knockout = anaesthetise.
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 ANAESTHETISE mean?

ANAESTHETISE verb
  1. To administer anesthesia to: to render unfeeling or unconscious through the use of narcotic substances, usually either alcohol or pharmaceutical drugs.

Latest crossword clues with full explanations