Compounds of 忽

• 忽
  (n) one hundred-thousandth
• 忽ち
  (adv) (uk) at once
  in a moment
  suddenly
  all at once
  (P)
• 忽然
  (adj-t,adv-to) sudden
  unexpected
• 粗忽
  (adj-na,n) careless
  thoughtless
  rash
  rude
  at fault
• 粗忽者
  (n) careless person
  thoughtless person