Green’s Dictionary of Slang

dynamiter n.

[dynamite v./dynamite n.2 (3)]

1. (US) a sponger, a cadger.

[US]Wash. Post 11 Nov. Miscellany 3/6: The terrible pseudonym ‘dynamiter’ is generally fastened on some harmless ‘blanket stiff’ who has specialized in chicken coops and in back doors for ‘hand outs’ on the ‘main stem.’.
[US]N. Anderson Hobo 101: [From A No. 1, The Famous Tramp] 40. Dino or Dynamiter. Sponged food of fellow hobos.
[US]Irwin Amer. Tramp and Und. Sl. 68: Dynamiter. – A tramp who begs from his fellows in preference to begging for his own food from the public, and thereby upsets all tramp custom. No real tramp or hobo with any pride will beg from another of his kind unless he has something to contribute in exchange.

2. (US) a very aggressive salesman.

[US]Flynn’s Weekly 13 Aug. in Partridge DU 219/2: Dynamiter [...] a clever, fast-working commercial swindler, esp. one who uses high-powered sales-talk.
[US]Sun (N.Y.) 19 Feb. 28/1: Financial racketeers have been less active since the securities act of 1933 and securities exchange act of 1934 were passed, but plenty of ‘dynamiters’ (high pressure salesmen of stock) are still out of jail.
[US]Goldin et al. DAUL 64/2: Dynamiter. [...] 2. A salesman of spurious stock, relatively crude in tactics. 3. (Prohibition era) A liquor salesman whose ‘buy-or-else’ suggestions were consistently effective.
[US](con. 1900-29) L. Katcher Big Bankroll 192: A dynamiter was the supervisor of a boiler room, the man who was called on to close the deals.

3. (US) a very ambitious person, a trouble-maker.

[US]Weseen Dict. Amer. Sl. 331: [General] Dynamiter – An aggressive and ambitious person.

4. (US drugs) a cocaine user.

[US]Goldin et al. DAUL 64/2: Dynamiter. 1. A cocaine addict.
[US]Anslinger & Tompkins Traffic In Narcotics 308: dynamiter. A cocaine addict.

5. (UK Und.) a drug pusher.

[UK](con. 1950s–60s) in G. Tremlett Little Legs 194: dynamiters drug-pushers.

6. see dynamite n.2 (6)