What is the meaning of Ne'er-do-well?

A person without a means of support; an idle, worthless person; a loafer; a person who is ineffectual, unsuccessful, or completely lacking in merit; a good-for-nothing.

A person who is up to no good; a rogue.

Showing the characteristics of a ne'er-do-well: indolent, worthless, or roguish.

Source: wiktionary.org