the.com/shake
Motion repeated fast enough to become a greeting, a threat, or a milkshake.
means To move something quickly back and forth, or the act and result of such trembling.
from From Old English sceacan, to move briskly or flee, sharing roots with words meaning to escape or vibrate across old Germanic tongues.
HandshakeLikely proved you hid no weapon.
Two shakesA lamb wags its tail surprisingly fast.
EarthquakeLiterally Earth shaking, no metaphor required.
MilkshakeOriginally an 1880s boozy, whiskey-laced drink.