Irresistible \Ir`re*sist"i*ble\, a. [Pref. ir- not + resistible: cf. F. irr['e]sistible.]

That can not be successfully resisted or opposed; superior to opposition; resistless; overpowering; as, an irresistible attraction.

An irresistible law of our nature impels us to seek happiness. --J. M. Mason.

Source: Webster's Revised Unabridged Dictionary (1913)