The most common and most likely answer to this crossword clue is the 4 letter word MINT
I've seen this crossword clue in The Guardian
M
I
N
T
More clues leading to the result MINT
Buddy explains!

The straight part
We know that "Perfect" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case perfect = mint.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 MINT mean?
MINT noun- A building or institution where money (originally, only coins) is produced under government licence.
- A large amount of money. A vast sum or amount, etc.
- Any place regarded as a source of unlimited supply; the supply itself.
- To reproduce (coins), usually en masse, under licence.
- To invent; to forge; to fabricate; to fashion.
- (with condition) Like new.
- In near-perfect condition; uncirculated.
- Unused with original gum; as issued originally.
- Very good.
- Attractive; beautiful; handsome.
- Any plant in the genus Mentha in the family Lamiaceae, typically aromatic with square stems.
- The flavouring of the plant, either a sweet, a jelly or sauce.
- Any plant in the mint family, Lamiaceae.
- A green colour, like that of mint.
- A mint-flavored candy, often eaten to sweeten the smell of the breath.
- Of a green colour, like that of the mint plant.
- (provincial) Intent, purpose; an attempt, try; effort, endeavor.
- (provincial) To try, attempt; take aim.
- (provincial) To try, attempt, endeavor; to take aim at; to try to hit; to purpose.
- To hint; suggest; insinuate.