catflap.org Online Dictionary Query

  be on the qui vive /biː ɒnðə kwi vˈaɪv/
  auf der Hut sein, wachsam sein
     Synonyms: be alert for trouble, be on (the) alert, be alert
  
   see: stiff hat, hat, titfer, stiff hats, hats, titfers, bucket hat, cloche hat, cloche, panama hat, panama, slouch hat, Tyrolean hat, Hats off to him!, You may just keep it (I don't want to have it)., unite different interest, be on one's guard, look out for squalls