1) Amazing 2) Astounding 3) Awe-inspiring 4) Breath-taking 5) Consuming 6) Demoralizing 7) Distressing 8) Disturbing 9) Grand 10) Humbling 11) Intense 12) Irresistible 13) Overpowering 14) Overriding 15) Overshadowing 16) Remarkable 17) Resistless 18) Shattering 19) Shocking 20) Splendid 21) Strong 1) Astonishing 2) Astounding 3) Awesome 4) Boggling 5) Consuming 6) Devastating 7) Huge 8) Indescribable 9) Indisputable 10) Insurmountable 11) Intense 12) Intimidating 13) Irresistible 14) Knockdown 15) Mind-boggling 16) Overpowering 17) Resistless 18) Sweeping 
• (p. pr. & vb. n.) of Overwhelm • (a.) Overpowering; irresistible.
O`ver·whelm'ing adjective Overpowering; irresistible. -- 
that overwhelms; overpowering: The temptation to despair may become overwhelming. · so great as to render resistance or opposition useless: an overwhelming majority.
[SAT terms] very intense