The word 'aggravate' entered English in the sixteenth century directly from the Latin past participle 'aggravātus,' from the verb 'aggravāre,' meaning 'to make heavier' or 'to increase the weight of.' Its literal sense is entirely physical: to add heaviness to something already heavy. The metaphorical leap from physical weight to worsened conditions happened in Latin itself, not in English.
The Latin verb is composed of 'ad-' (to, toward — assimilated to 'ag-' before 'g') and 'gravāre' (to weigh down, to burden), derived from the adjective 'gravis' (heavy, weighty, serious). Latin 'gravis' comes from the Proto-Indo-European root *gʷreh₂-, meaning 'heavy,' one of the ancient language family's fundamental descriptors of the physical world.
The PIE root *gʷreh₂- split into several channels as it descended through the daughter languages. In Latin, 'gravis' and its derivatives became the primary heavy-word family: 'gravitas' (heaviness, seriousness — borrowed into English as a term for dignified seriousness), 'gravitās' (which Newton adopted in 1687 as 'gravity' for the force that makes things heavy), 'gravāre' (to burden), and 'gravidus' (heavy with child, pregnant — hence English 'gravid'). The musical term 'grave' (played slowly and solemnly) also comes from 'gravis.'
In Greek, the labial quality of the PIE labiovelar *gʷ was preserved as 'b,' yielding 'barys' (βαρύς), meaning 'heavy' or 'deep.' From this Greek adjective came 'baritone' (a heavy or deep voice), 'barometer' (a measure of atmospheric weight/pressure), and 'barium' (the heavy element). The phonological divergence between Latin 'gr-' and Greek 'b-' from the same PIE source is a textbook example of how sound laws transform cognates beyond easy recognition.
In Sanskrit, the same root produced 'guru,' meaning 'heavy' and, by extension, 'weighty' in the sense of 'important' or 'venerable' — hence a spiritual teacher of great weight and authority. The English borrowing 'guru' thus shares its ultimate root with 'gravity,' 'grave,' and 'aggravate.'
The informal sense of 'aggravate' meaning 'to annoy' or 'to irritate' — as in 'stop aggravating me' — has been controversial among prescriptivists since at least the eighteenth century. Purists insist that 'aggravate' should only mean 'to make worse' (you aggravate a wound, not a person). But the 'annoy' sense has been documented since the early seventeenth century, and the semantic path is natural: something that makes a situation heavier is burdensome, and being burdened is annoying. The informal usage is now standard in spoken English, though careful writers in formal contexts still prefer the 'make worse' sense.
Legal English preserves the original Latin sense precisely. 'Aggravated assault' means an assault made worse by additional factors — the use of a weapon, the vulnerability of the victim, or the intent to commit a further crime. An 'aggravating circumstance' in sentencing is one that adds weight to the severity of an offense. In both cases, the word functions exactly as the Romans intended: adding heaviness to something already heavy.
The word 'aggravate' thus stands at the intersection of physics and metaphor. Its journey from PIE heaviness through Latin legal and medical terminology to modern informal speech illustrates how a concrete physical sensation — the feeling of added weight — can be abstracted into notions of worsening, burdening, and finally mere irritation.