Lacking courage, spirit, or energy; timid, faint-hearted; lazy, negligent. Now English regional (chiefly northern).

Of persons: lacking in energy or diligence; inclined to be lazy or idle; remiss, careless; negligent or lax in regard to one's duties.

? Lacking in diligence; slack.

Having the energies, attention, etc. relaxed; wanting firmness, strictness, or assiduity; loose, lax, slack, careless, negligent, remiss. Obsolete.

Defective, flawed, faulty. Of a person: at fault; guilty, esp. of failure in the performance of a duty or obligation.

At fault, remiss. Also: faulty, defective, flawed.

Careless, negligent; = remiss, adj. 3a, 3b. Also with of.

Characterized by a lack of strictness or proper restraint; lax, undisciplined.

Slack, remiss. rare.

(un-, prefix1 affix 2.)

(un-, prefix1 affix 1.)

Lax, undisciplined; dissolute. Later also (with conscious reference to the etymology): not wearing a belt or girdle.

Not officious (in various senses). In later use esp.: disinclined to intervene; unobtrusive.

The opposite of industrious; unindustrious.

Not diligent; idle, slothful.

Of clothes: Loose-fitting, worn loosely. Of persons: Negligent in attire and deportment. Of handwriting: Not compact; also, careless, not precise…

Careless, negligent.