The most common and most likely answer to this crossword clue is the 4 letter word CALF
I've seen this crossword clue in Financial Times
C
A
L
F
More clues leading to the result CALF
- Young trumpeter’s signal that’s short and loud
- Young elephant is mostly placid with female
- Starts to compile, and later finishes new jumbo?
- Part of leg in young animal
- Man’s neighbour is a little beast
- Young creature giving rise to endless criticism
- Youngster left in coffee house refusing drug
- Knee higher – this lower?
- A little lower – down the leg
- Part of leg from young elephant
Buddy explains!

The straight part
We know that "Youngster" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case youngster = calf.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 CALF mean?
CALF noun- A young cow or bull.
- Leather made of the skin of the calf; especially, a fine, light-coloured leather used in bookbinding.
- A young deer, elephant, seal, whale or giraffe (also used of some other animals).
- A chunk of ice broken from a larger glacier, ice shelf, or iceberg.
- A small island, near a larger island.
- A cabless railroad engine.
- An awkward or silly boy or young man; any silly person; a dolt.
- The back of the leg below the knee.
- The muscle in the back of the leg below the knee.