要不

yàobù
  1. otherwise
  2. or else
  3. how about...?
  4. either... (or...)

CEDICT

Entry Composition

1 要 yào
  1. to want; to need; to ask for
  2. will; shall; about to
  3. need to; should
  4. if (same as 要是 yàoshi)
  5. (bound form) important
2 不 bù
  1. no; not so
  2. (bound form) not; un-