restive (adj.)

[be left, remain] mid-15c., "remain, continue in existence," from Old French rester "to remain, stay" (12c.), from Latin restare "stand back, be left," from re- "back" (see re-) + stare "to stand" (from PIE root *sta- "to stand, make or be firm").

It has been largely confused and partly merged with rest (v.1), which, however, is Germanic.

The meaning "be in a certain state or position" (of affairs, etc.) is from late 15c.  The older sense of "to continue to be" is rare but in phrases such as rest assured. To rest with "be in the power of, depend upon" is by 1819.

The transitive sense of "to keep, cause to continue to remain" was common in 16c.-17c., "used with a predicate adjective following and qualifying the object" [Century Dictionary]. Hence the phrase rest you merry (1540s, Shakespeare also has rest you fair), earlier rest þe murie (mid-13c.), as a greeting, "rest well, be happy," from the old adverbial use of merry. The Christmas carol lyric God rest ye merry, gentlemen, often is mispunctuated.

"to cause to stop," also "to detain legally," late 14c., from Old French arester "to stay, stop" (12c., Modern French arrêter), from Vulgar Latin *arrestare "to stop, restrain" (source also of Italian arrestare, Spanish and Portuguese arrestar), from ad "to" (see ad-) + Latin restare "to stop, remain behind, stay back," from re- "back" (see re-) + stare "to stand" (from PIE root *sta- "to stand, make or be firm"). The figurative sense of "to catch and hold" (the attention, etc.) is from 1814.