Usually written in standard English as "Pushin' Weight," this phrase was popularised by Ice Cube (the great) who proclaimed that "Yeah Yeaaaaah-" he in fact "pushed rhymes
like weight."
The phrase, a combination of the two root words, "Push" and, well..."weight," is a milestone in urban language. The former is an
American slang term most commonly used to refer to the action of dealing (e.g. drugs) in a semi-forceful way. The latter word of the phrase is defined throughout this glorious site as
cocaine, which as Rick James informed
us, is "a hell of a drug" (see also "blow", "yaio".)