The most common and most likely answer to this crossword clue is the 6 letter word STASES
S
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A
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More clues leading to the result STASES
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The straight part
We know that "periods of inactivity" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case periods of inactivity = stases.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 STASES mean?
STASES 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.