obnoxious

adjective

1. highly objectionable or offensive; odious: obnoxious behavior.
2. annoying or objectionable due to being a showoff or attracting undue attention to oneself: an obnoxious little brat.
3. Archaic. exposed or liable to harm, evil, or anything objectionable.
4. Obsolete. liable to punishment or censure; reprehensible.

adjective

1. extremely unpleasant
2. obsolete exposed to harm, injury, etc

adj.1580s, “subject to the authority of another,” from Latin obnoxiosus “hurtful, injurious,” from obnoxius “subject, exposed to harm,” from ob “to, toward” (see ob-) + noxa “injury, hurt, damage entailing liability” (see noxious). Meaning “subject to something harmful” is 1590s; meaning “offensive, hateful” is first recorded 1670s, influenced by noxious. Obnoxious has two very different senses, one of which (exposed or open or liable to attack or injury) requires notice because its currency is now so restricted that it is puzzling to the uninstructed. It is the word’s rightful or de jure meaning, and we may hope that scholarly writers will keep it alive. [Fowler] Related: Obnoxiously; obnoxiousness.