irregular

Nonstandard; not conforming to rules or expectations.

‘ “It would be most irregular Grandpa!” says Miss Cecily frowning and tapping her foot. “Well, we’re a pretty irregular family so that’s neither here nor there,” says the old man, impish like. [...] ’

Rough (of a surface).

Without symmetry, regularity, or uniformity.

The hovel stood in the centre of what had once been a vegetable garden, but was now a patch of rank weeds. Surrounding this, almost like a zareba, was an irregular ring of gorse and brambles, an unclaimed vestige of the original common.

Near by, where the crystal clear River Llugwy is crossed by a bridge, stands a small and ancient church built of massive, irregular boulders.

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).

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.

There's one neighborhood tavern where the regulars and irregulars go after a hard day to unlax and rewind, throw back a few, and just hang out - you know the one.