blow (v.1) Look up blow at Dictionary.com
"move air," O.E. blawan "blow, breathe, make an air current; kindle; inflate; sound a wind instrument" (class VII strong verb; past tense bleow, pp. blawen), from P.Gmc. *blæ-anan (cf. O.H.G. blaen, Ger. blähen), from PIE *bhle- "to swell, blow up" (cf. L. flare "to blow"). Slang "do fellatio on" sense is from 1933, as blow (someone) off, originally among prostitutes (cf. blow job). This usage is probably not connected to the colloquial imprecation (1781, associated with sailors, e.g. Popeye's "well, blow me down!"), which has pp. blowed. Meaning "to spend (money) foolishly and all at once" is 1890s; that of "bungle an opportunity" is from 1943.
blow (v.2) Look up blow at Dictionary.com
"to bloom, blossom" (intrans.), from O.E. blowan "to flower, blossom, flourish," from P.Gmc. *blæ- (cf. O.S. bloian, O.Fris. bloia, O.H.G. bluoen, Ger. blühen), from PIE *bhle-, extended form of *bhel- (2) "to thrive, bloom" (see bole). This word is the source of the blown in full-blown.
blow (n.) Look up blow at Dictionary.com
"hard hit," mid-15c., blowe, from northern and East Midlands dialects, perhaps from M.Du. blouwen "to beat," a common Germanic word of unknown origin (cf. Ger. bleuen, Goth. bliggwan "to strike"). Influenced in English by blow (v.1).