craziness

1. The state of being broken down or weakened; as, the craziness of a ship, or of the limbs.

2. The state of being broken in mind; imbecility or weakness of intellect; derangement.

noun

1. Serious mental illness or disorder impairing a person's capacity to function normally and safely: brainsickness, dementia, derangement, disturbance, insaneness, insanity, lunacy, madness, mental illness, psychopathy, unbalance. Psychiatry mania. Psychology aberration, alienation. See sane/insane.
2. Foolish behavior: absurdity, folly, foolery, foolishness, idiocy, imbecility, insanity, lunacy, madness, nonsense, preposterousness, senselessness, silliness, tomfoolery, zaniness. See ability/inability.

The noun has 2 meanings:

Meaning #1: informal terms for insanity
  Synonyms: daftness, flakiness

Meaning #2: the quality of being rash and foolish
  Synonyms: folly, foolishness