blow

   1. obsolete (of a male)

   to copulate

   Usually in a phrase such as blow the groundsels, which meant that the parties were on the floor at the time. To blow ojff is to ejaculate semen:

    Blew off all over the booth. {Playboy's Book of Limericks)

   2. American

   a prostitute

   A shortened form of the obsolete blowen, perhaps.

   3. orally to excite the genitals of another

   Homosexually or heterosexually:

    He was cruising down the interstate and his daughter's husband is blowing him. (Diehl, 1978)

   A blow job is such activity:

    'You want me to give you a blow job?' She got off the bed and came towards him. (Sharpe, 1976)

   4. (off)

   to fart

   A common vulgarism. See also blow a raspberry.

   5. to boast

   Seldom in modern use tout court but usually in a phrase such as blow smoke, blow your own horn, or blow your own trumpet:

    You think I'm blowing smoke? (Sanders, 1994)

    Some staff member or some consultant can blow his horn and look oh, so smart and oh, so good to some journalist. {Daily Telegraph, 11 January 1997, quoting President Clinton)

   6. a mild oath

   Of the same tendency as blast¹.

   7. to betray to authority

   Probably a shortened form of blow away or blow up, to lose or destroy:

    Did you tell the man to blow me? (Hall, 1979 — the speaker is a betrayed spy)

   The British blow the gaff means to betray or give away confidential information, gaff being gossip.

   See also blow the whistle on.

   8. an illegal narcotic

   The common imagery of hitting:

    And did Hardcore tell you that the idea was to make it look like this white man had been killed in a drive-in while he was buying blow? (Turow, 1996)

   Also, as a verb, to smoke such a narcotic, in phrases such as blow a stick, Charlie, horse, snow, etc.