Green’s Dictionary of Slang

scruff n.

[dial. scruff, refuse, thus human refuse in dial. use since mid-19C; ult. SE scurf]

1. [1950s+] an unkempt, messy person; also a term of abuse.

2. [1990s+] pornographic literature.

In compounds

scruff-bag (n.) [-bag sfx] [1920s+]

1. a down-and-out.

2. a messy, unkempt person (or animal, see cit. 1987).

3. attrib. use of sense 2.

scruff-hound (n.) [-hound sfx]

[1940s] a rough, tough individual.