The most common and most likely answer to this crossword clue is the 7 letter word HOTSPUR
I've seen this crossword clue in The Times
H
O
T
S
P
U
R
More clues leading to the result HOTSPUR
- Percy with time to grab teaspoon
- Percy is in demand on branch line
- Proust translated by Henry Percy
- Percy associated with Tottenham
- Impulsive Shakespearean spiced up secondary line
- According to Spooner, catch sight of the female firebrand
- Henry turned up to motivate Percy
- Sexy urge for Shakespeare’s Percy
- Popular incentive for knight
- Fiery type in Proust novel going after husband
Buddy explains!

The straight part
We know that "knight" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case knight = hotspur.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 HOTSPUR mean?
HOTSPUR noun- Somebody who is rash, impetuous or impulsive.