Incongruous vs. Ludicrous — What's the Difference?

Lacking in harmony; incompatible

So absurd or incongruous as to be laughable.

Not in agreement, as with principles; inconsistent

Idiotic or unthinkable, often to the point of being funny; amusing by being plainly incongruous or absurd.

Not in keeping with what is correct, proper, or logical; inappropriate

Adapted to excite laughter, without scorn or contempt; sportive.

Not similar or congruent; not matching or fitting in.

Ridiculously absurd.

(math) Of two numbers, with respect to a third, such that their difference can not be divided by it without a remainder.

Broadly or extravagantly humorous; resembling farce;

Not congruous; reciprocally disagreeing; not capable of harmonizing or readily assimilating; inharmonious; inappropriate; unsuitable; not fitting; inconsistent; improper; as, an incongruous remark; incongruous behavior, action, dress, etc.

Completely devoid of wisdom or good sense;

Lacking in harmony or compatibility or appropriateness;