impetus (n.)
- acceleration
- activity
- animation
- ardor
- brio
- briskness
- catalyst
- clout
- compulsion
- drive
- elan
- encouragement
- energy
- enthusiasm
- getaway
- glow
- goad
- gusto
- impetuosity
- impulse
- impulsion
- incentive
- incitation
- incitement
- inspiration
- life
- liveliness
- lustiness
- mettle
- moment
- momentum
- motivation
- perkiness
- pertness
- pickup
- power
- propulsion
- push
- quickening
- robustness
- speedup
- spirit
- spiritedness
- spur
- step-up
- stimulant
- stimulation
- stimulus
- thrust
- vivacity
- warmth
- zest
- zestfulness
