resistless adjective. 
[rɪ'zɪs(t)lɪs] Now 
arch. & 
poet. L16.[from RESIST + -LESS.]1.  That cannot be withstood; irresistible. 
L16.2.  Powerless to resist; unresisting. 
L16. ■   resistlessly adverb E18. ■   resistlessness noun L19.  [TahlilGaran] English Dictionary ▲