slant v.

1520s, "to strike obliquely" (against something), alteration of slenten "slip sideways" (c. 1300), perhaps via a Scandinavian source (compare Swedish slinta "to slip," Norwegian slenta "to fall on one side"), from Proto-Germanic *slintanan.

The intransitive sense of "to slope, to lie obliquely" is recorded by 1690s; transitive sense of "to give a sloping direction to" is from 1805. Related: Slanted; slanting. As an adverb from late 15c.; as an adjective from 1610s. Poetic slant rhyme "assonance or consonance" is attested by 1926.

1650s, "an oblique direction or plane" (originally of landforms), from slant (v.) or its adjective. The meaning "way of regarding something, a mental bias" is from 1905. Derogatory slang sense of "slant-eyed Asian person" is recorded from 1943, from earlier slant-eyes (1929).