(a.) Done in a moment; lasting a very short time; as, a momentary pang\.

annual biannual biennial bimonthly biweekly brief brittle capricious catamenial centenary centennial changeable corruptible daily decennial deciduous diurnal dying ephemeral evanescent fading fickle fleeting flitting fly-by-night flying fortnightly fragile frail fugacious fugitive hasty hebdomadal hourly immediate impermanent impetuous impulsive inconstant instant instantaneous insubstantial lightning-like menstrual momentaneous momently monthly mortal mutable nondurable nonpermanent passing perishable presto quarterly quick quick as lightning quick as thought quotidian secular semestral semiannual semimonthly semiweekly semiyearly short short-lived temporal temporary tertian transient transitive transitory triennial undurable unenduring unstable volatile weekly yearly