vac/van/void

empty

Spelled vac, van, void · vacuus 'empty'; vacare 'be empty or free'; vanus 'empty, vain'

Latin vacuus means empty: a vacant room lacks occupants, a vacuum lacks matter, and vacuous talk lacks ideas.

Words built from it

vacant — empty or unoccupied
Latin vacare (be empty) → vacans, vacant- (being empty) → vacant
vacuous — lacking meaningful thought or content
Latin vacuus (empty) + -ous (having the quality of)
vacuum — a space containing no matter, or very little matter
Latin vacuum (an empty space), the neuter noun form of vacuus (empty)
evacuate — remove people from a dangerous place
Latin e- (out) + vacuare (empty), from vacuus (empty) → evacuare (empty out)
evanescent — quickly fading or disappearing
Latin e- (away) + vanescere (vanish), from vanus (empty) → evanescens (vanishing)
vanish — disappear from sight or cease to exist
Latin vanus (empty) → vanescere (disappear) → Old French vaniss-, a stem of vanir → vanish
vanity — excessive pride in one's appearance or achievements
Latin vanus (empty, vain) → vanitas (emptiness, worthlessness) → Old French vanité → vanity
void — empty; without legal force
Latin vacare (be empty) → vacivus (empty), with variant vocivus → Old French voide → void

vacillate — From Latin vacillare, 'sway or stagger.' It means waver between choices and does not descend from the root meaning 'empty.'