Green’s Dictionary of Slang

natural n.

1. when pertaining to a ‘state of nature’.

(a) [mid-16C+] an idiot; one who is untutored or unsophisticated; often the potential victim of a confidence trick.

(b) [late 17C–early 19C] a mistress; a prostitute.

(c) [late 17C–early 19C] an illegitimate child.

2. pertaining to gambling [abbr. SE natural winner].

(a) [mid-18C; late 19C–1960s] (gambling) a winning combination, esp. in craps.

(b) [1900s–30s] fig. use of sense 2a, good luck.

(c) [1930s–40s] (US prison) ext. use of sense 2a, a seven-year sentence.

3. [mid-18C; 1920s+] (orig. US) one who is naturally suited to a job or skill; one who is naturally talented.

4. when pertaining to ‘one’s natural life’.

(a) [late 19C+] (also nat) one’s life.

(b) [1900s-30s] (US) a life sentence.

5. [1920s+] (US) something certain to succeed, a winner; something inevitable.

6. [1960s+] (US black, also natch, natchie) a bushy hairstyle, in which one’s hair is allowed to grow naturally, rather than being subjected to straightening or similar styling.

7. [1970s+] (US black) one’s ‘natural-born’ self.

In compounds

natural pick (n.) (also pick) [SE pick, a pointed tool, here a comb]

[1960s+] (US black) a large comb used spec. for tidying an afro n. (1) or ‘natural’ hairstyle.

In phrases

all one’s natural [abbr. SE phr. all one’s natural born days]

[late 19C+] all one’s life .

for one’s natural

as if one’s life depended on it.

get off the natural (v.)

[1960s] (US drugs) to become intoxicated.

not on your natural [abbr. SE natural life, thus var. on not on your life (see under life n.)]

[20C+] absolutely not.

throw a natural (v.) [sense 1b above]

[1900s] to experience good luck.