Not efficient; not producing the effect intended or desired; inefficacious
Incapable of, or indisposed to, effective action; habitually slack or unproductive; effecting little or nothing
A person who cannot or does not work efficiently.
nonstandard; not conforming to rules or expectations
without symmetry, regularity, or uniformity
rough
not regular; having sides that are not equal or angles that are not equal
whose faces are not all regular polygons (or are not equally inclined to each other)
not following the regular or expected patterns of inflection in a given language
A soldier who is not a member of an official military force and who may not use regular army tactics.
One who does not regularly attend a venue.