Thayer's Greek Lexicon

 1. to guard
  1) to watch, keep watch
  2) to guard or watch, have an eye upon: lest he escape
  3) to guard a person (or thing) that he may remain safe
1c1. lest he suffer violence, be despoiled, etc. to protect
1c2. to protect one from a person or thing
1c3. to keep from being snatched away, preserve safe
and unimpaired
1c4. to guard from being lost or perishing
1c5. to guard one's self from a thing
  4) to guard i.e. care for, take care not to violate
1d1. to observe
2. to observe for one's self something to escape
  1) to avoid, shun flee from
  2) to guard for one's self (i.e. for one's safety's sake) so
as not to violate, i.e. to keep, observe (the precepts of
the Mosaic law)

For Synonyms see entry G5874