Source : Webster's Revised Unabridged Dictionary (1913)

Succumb \Suc*cumb"\, v. t. [imp. & p. p. {Succumbed}; p. pr. &
   vb. n. {Succumbing}.] [L. succumbere; sub under + cumbere (in
   comp.), akin to cubare to lie down. See {Incumbent},
   {Cubit}.]
   To yield; to submit; to give up unresistingly; as, to succumb
   under calamities; to succumb to disease.

Source : WordNet®

succumb
     v 1: consent reluctantly [syn: {yield}, {give in}, {knuckle under},
           {buckle under}]
     2: be fatally overwhelmed [syn: {yield}] [ant: {survive}]