The most common and most likely answer to this crossword clue is the 3 letter word ELF
I've seen this crossword clue in The Times
E
L
F
More clues leading to the result ELF
- Sprite seen in hotel foyer
- Fairy in novel
- Mischief maker well-off but oddly lacking
- Regularly tell off mischievous child
- Supernatural creature nearly flew over
- Mischievous child ’s identity, the first to be concealed
- Fairy’s personality not singular
- Spirit soared briefly upward
- Trouble-maker turning up in row I avoided
- In Catalonia, the fine, mischievous spirit
Buddy explains!

The straight part
We know that "Fairy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fairy = elf.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 ELF mean?
ELF noun- A luminous spirit presiding over nature and fertility and dwelling in the world of Álfheim (Elfland). Compare angel, nymph, fairy.
- Any from a race of mythical, supernatural beings resembling but seen as distinct from human beings. They are usually delicate-featured and skilled in magic or spellcrafting; sometimes depicted as clashing with dwarves, especially in modern fantasy literature.
- Any of the magical, typically forest-guarding races bearing some similarities to the Norse álfar (through Tolkien's Eldar).
- A very diminutive person; a dwarf.
- The bluefish (Pomatomus saltatrix).
- To twist into elflocks (of hair); to mat.