Latin for 'to make heavier' — from 'gravis' (heavy), so to aggravate is to pile on weight.
To make a problem, injury, or offense worse or more serious; (informal) to annoy or exasperate someone.
From Latin aggravatus, past participle of aggravare (to make heavier, to add weight to), composed of ad- (to, toward) + gravare (to weigh down), from gravis (heavy, weighty, serious). Latin gravis derives from PIE *gwreh2- (heavy), which produced Greek barys (heavy) — with the characteristic Greek shift of *gw to b — Sanskrit guru (heavy, weighty, venerable — the source of "guru," literally "the weighty/authoritative one"), Gothic kaurus (heavy), and Old English cweorn (a hand-mill, something heavy to turn). The Latin meaning was strictly "to make heavier, to add weight to a burden" — you aggravated a wound by making it worse, or aggravated a legal penalty by increasing it. English borrowed it from Latin in the 16th century with this precise sense
To 'aggravate' literally means 'to add weight to.' The same Latin root 'gravis' (heavy) produced 'gravity' (heaviness), 'grave' (heavy, serious), 'grieve' (to feel heavy sorrow), and — through Greek 'barys' (heavy) — 'baritone' (a heavy/deep voice). Even Sanskrit 'guru' (weighty, hence a teacher of weight) comes from the same PIE root.