noun

• (chiefly Canada, US, Australia, New Zealand, South Africa, India, Philippines, Singapore, Northern England) An outer garment that covers the body from the waist downwards, covering each leg separately, usually as far as the ankles; trousers.
  "“But they cover the legs,” Joseph explained. “That is the only reason my people wear pants: to cover the legs in the winter, or when traveling through rough country, full of thorns. In warm weather, or in open country, pants are unnecessary, uncomfortable, and foolish.”"
• (chiefly UK) An undergarment that covers the genitals and often the buttocks and the neighbouring parts of the body; underpants.
  "I decided to pass up her underclothes, not from feelings of delicacy, but because I couldn't see myself putting her pants on and snapping her brassière."
• (UK, slang) Rubbish; something worthless.
  "You're talking pants!"

adj

• (British, slang) Of inferior quality, rubbish.
  "Your mobile is pants — why don’t you get one like mine?"