Vexatious means causing annoyance and needless trouble. A vexatious delay, vexatious neighbours, vexatious in the extreme.
In law it is a term of art, and a vexatious claim is one brought to harass rather than to win. Outside law it is a mild and rather old-fashioned complaint.
1adjectivevexatiousCausing annoyance and needless trouble.
“The court struck the case out as vexatious.”
vexatious is a quality.
Vexation plus -ous, from Latin vexare, to shake or harass.
Proto-Indo-European
*weǵʰ-
Latin
vexātiō — shaking or similar violent movement; (causing of) agitation, distress, suffering; harassment, persecution; trouble
Old French
vexacion
Middle French
vexacion
Anglo-Norman
vexacion
Middle English
vexacioun
English
vexation
English, today
vexatious
Built from
a 1650 vexation + ous vexation comes from Late Middle English vexacioun, vexation (“physical suffering; act of inflicting trouble (specifically through unjustified legal action); anxiety, mental distress; mental disturbance”), from Anglo-Norman vexacion, vexation, Middle French vexacion, vexation (“distress, suffering; harassment (specifically through unjustified legal action)”), and Old French vexacion, vexation (“distress, suffering; harassment”) (modern French vexation), and from their etymon Latin vexātiō (“shaking or similar violent movement; (causing of) agitation, distress, suffering; harassment, persecution; trouble”), from vexātus + -iō. Vexātus is the perfect passive participle of vexō (“to shake or jolt violently; to annoy, harass; to persecute; to trouble violently”), ultimately from Proto-Indo-European weǵʰ-. by surface analysis, vex + -ation. a doublet of quake.
Etymology from Wiktionary, CC BY-SA