The most common and most likely answer to this crossword clue is the 6 letter word STASIS
I've seen this crossword clue in Financial Times
S
T
A
S
I
S
More clues leading to the result STASIS
- Briefly remain with relative in stable condition
- Old police sergeant's first arrest
- Arrest reversed during crisis at surgery
- Period of inactivity in rest, as I sit
- International exams recalled by head of school — still time?
- Dreaded police before second arrest
- Way a sun exists in a constant state
- Police officers once last in exams — still time!
- Lack of movement with thoroughfare in its present condition
- Time in army unit is a constant equilibrium
Buddy explains!

The straight part
We know that "a constant equilibrium" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a constant equilibrium = stasis.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 STASIS mean?
STASIS noun- A slackening or arrest of the blood current, due not to a lessening of the heart’s beat, but to some abnormal resistance of the capillary walls.
- Inactivity; a freezing, or state of motionlessness.
- A technology allowing something to be artificially frozen in time, so that it does not age or change.
- One of the sections of a cathisma or portion of the psalter.