1. that falls or has fallen, falling, collapsing, drooping.
2. that easily falls, inclined to fall.
3. devoted to death, destined to die, doomed.
4. Figuratively: frail, fleeting, perishable, transitory; vain, futile.
5. Law: lapsed, vacant, escheatable, caducary.
Etymology: from Latin cadūcus, from cadō, “I fall”.
[Eric Armusik - Flight of Icarus]