Of a person or (occasionally) an animal: having uncombed or untidy hair; (hence) scruffy or dishevelled in appearance.

Not mustered; not formally enrolled into military service.

(un-, prefix1 affix 2.)

Of or relating to vagrants or loafers; resembling or suggestive of a bum (bum, n.6 3a); scruffy, unkempt.

Unprepossessing in appearance or disposition; unkempt; disreputable, contemptible, decrepit.

Esp. of a man: unattractive or plain-looking; shabbily dressed; unkempt.