The most common and most likely answer to this crossword clue is the 11 letter word ROPE-A-DOPE
I've seen this crossword clue in Independent
R
O
P
E
-
A
-
D
O
P
E
Buddy explains!
The straight part
We know that "How to box" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case how to box = rope-a-dope.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 ROPE-A-DOPE mean?
ROPE-A-DOPE noun- A technique in which the boxer assumes a defensive stance against the ropes and absorbs an opponent's blows, hoping to exploit eventual tiredness or a mistake.
- Any strategy where an apparently losing position is assumed in the hope of eventual victory.
- To exhaust someone by stringing them along.