The most common and most likely answer to this crossword clue is the 4 letter word PUNK
P
U
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More clues leading to the result PUNK
Buddy explains!

The straight part
We know that "delinquent" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case delinquent = punk.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 PUNK mean?
PUNK noun- A person used for sex, particularly:
- A worthless person, particularly:
- Short for punk rock, a genre known for short, loud, energetic songs with electric guitars and strong drums.
- Short for punk rocker, a musician known for playing punk rock or a fan of the genre.
- The larger nonconformist social movement associated with punk rock and its fans.
- To pimp.
- To forcibly perform anal sex upon an unwilling partner.
- To prank.
- (especially with "out") To give up or concede; to act like a wimp.
- (often with "out" or "up") To adapt or embellish in the style of the punk movement.
- Worthless, contemptible, particularly
- Of or concerning punk rock or its associated subculture.
- Any material used as tinder for lighting fires, such as agaric, dried wood, or touchwood, but especially wood altered by certain fungi.
- A utensil for lighting wicks or fuses (such as those of fireworks) resembling stick incense.