不由

bùyóu
can't help (doing sth)

CEDICT

Entry Composition

1 不 bù
  1. no; not so
  2. (bound form) not; un-
2 由 yóu
  1. to follow
  2. from
  3. because of; due to
  4. by; via; through
  5. (before a noun and a verb) it is for ... to ...