The most common and most likely answer to this crossword clue is the 6 letter word STRAIN
I've seen this crossword clue in The Times
S
T
R
A
I
N
More clues leading to the result STRAIN
- Provincial theatre etc facing up to pressure
- Son taking school test fully
- Separate and distinct group
- Son's direct descendants
- Make excessive demands on second rail service
- Muscle problem ultimately defeats coach
- Make all-out effort, producing a little music
- Labour wants second rail service
- Way inclement weather produces stress
- Mark King’s cracking melody
Buddy explains!

The straight part
We know that "stress" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case stress = strain.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 STRAIN mean?
STRAIN noun- Treasure.
- The blood-vessel in the yolk of an egg.
- Race; lineage, pedigree.
- Hereditary character, quality, or disposition.
- A tendency or disposition.
- Any sustained note or movement; a song; a distinct portion of an ode or other poem; also, the pervading note, or burden, of a song, poem, oration, book, etc.; theme; motive; manner; style
- A particular breed or race of animal, microbe etc.
- A portion of music divided off by a double bar; a complete musical period or sentence; a movement, or any rounded subdivision of a movement.
- A kind or sort (of person etc.).
- Language that is eloquent, poetic, or otherwise heightened.
- The act of straining, or the state of being strained.
- A violent effort; an excessive and hurtful exertion or tension, as of the muscles.
- An injury resulting from violent effort; a sprain.
- A dimensionless measure of object deformation either referring to engineering strain or true strain.
- The track of a deer.
- To hold tightly, to clasp.
- To apply a force or forces to by stretching out.
- To damage by drawing, stretching, or the exertion of force.
- To act upon, in any way, so as to cause change of form or volume, as when bending a beam.
- To exert or struggle (to do something), especially to stretch (one's senses, faculties etc.) beyond what is normal or comfortable.
- To stretch beyond its proper limit; to do violence to, in terms of intent or meaning.
- To separate solid from liquid by passing through a strainer or colander
- To percolate; to be filtered.
- To make uneasy or unnatural; to produce with apparent effort; to force; to constrain.
- To urge with importunity; to press.
- Hug somebody; to hold somebody tightly.
- To beget, generate (of light), engender, copulate (both of animals and humans), lie with, be born, come into the world.