shit

Concise Oxford English Dictionary © 2008 Oxford University Press:
shit /ʃɪt/ vulgar slang

▶noun

• 1 faeces.

  ■ an act of defecating.

• 2 a contemptible person.

• 3 something worthless; rubbish; nonsense.

• 4 an intoxicating drug, especially cannabis.

▶verb (shits, shitting; past and past part. shitted or shit or shat)

• 1 defecate.

• 2 (shit oneself) be very frightened.

▶exclamation expressing disgust or annoyance.

– phrases
be shitting bricks be extremely nervous or frightened.
in the shit in trouble.
not give a shit not care at all.
be up shit creek (without a paddle) be in an awkward predicament.
when the shit hits the fan when the disastrous consequences of something become known.

– origin OE scitte ‘diarrhoea’, of Gmc origin.