Source : Webster's Revised Unabridged Dictionary (1913)

Slantwise \Slant"wise`\, Slantly \Slant"ly\, adv.
   In an inclined direction; obliquely; slopingly.

Source : WordNet®

slantwise
     adv : at a slant; moving or directed in a slantwise position or
           direction [syn: {slantways}]