Thayer's Greek Lexicon

 1. to stand beside and watch, to watch assiduously, observe carefully
  1) to watch, attend to with the eyes
  1) of auguries, to see what he is going to do
  2) in a bad sense, to watch insidiously
  3) to watch one's self
  2) to observe, keep scrupulously
1b1. to neglect nothing requisite to the religious observance of