parlous
Attended with peril; dangerous, risky.
The situation became parlous when the weather made resupply impossible.
Appalling, dire, terrible.
All whiche offences and mysdemenors abovesaid have bene commytted to the grete hurte and undoyng of your orator, and the right evill and parlous example, [etc.]; […]
Dangerously clever or cunning; also, remarkably good or unusual.
obsolete, rare
A parlous Boy: go too, you are too ſhrew'd.
Where it comes from
From Middle English parles, parlous, perlous, [and other forms], a contraction of perilous (“dangerous; dreadful, terrible; morally corrupt, sinful, wicked; inauspicious, unlucky”) (and thus a doublet of perilous), from Old French perilleus, perillos, perillous, perilluse, perilleuse, perilleux (“very dangerous, perilous”) (modern French périlleux), from Latin perīculōsus (“dangerous, hazardous, perilous”), from perīculum (“danger, hazard, peril, risk”) (ultimately from Proto-Indo-European *per- (“to go through, carry forth, try”)) + -ōsus (suffix meaning ‘full of, prone to’ forming adjectives).
Adapted from the Wiktionary entry parlous (CC BY-SA 4.0).