The most common and most likely answer to this crossword clue is the 4 letter word TAUT
I've seen this crossword clue in The Guardian
T
A
U
T
More clues leading to the result TAUT
- Given coaching in voice that's showing strain
- Tense, gave instruction in speech
- Jeer with any number leaving stressed
- Gave instruction as audibly stressed
- By the sound of it, worked in education, far from relaxed
- Like school pupil sounding unrelaxed
- Tense, as trained for audition?
- Tense, given instruction in hearing
- Articulate wrong tense
- Tense, as is pupil in audition
Buddy explains!

The straight part
We know that "unrelaxed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unrelaxed = taut.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 TAUT mean?
TAUT verb- To make taut; to tauten, to tighten.
- Under tension, like a stretched bowstring, rope, or sail; tight.
- (of a body, muscles, etc.) Not flabby; firm, toned; (of a person) having a lean, strong body.
- (of music, writing, etc.) Containing only relevant parts; brief and controlled.
- Experiencing anxiety or stress.
- (of a sailor, a ship, etc.) Neat and well-disciplined; (by extension) efficient and in order.
- Strong; uncompromising.