RichThesaurus
Argus-eyed
vs
on the qui vive
Argus-eyed
adj
ever vigilant
on the qui vive
adv
In a state of heightened vigilance, especially prior to battle.
How often have the words
Argus-eyed
and
on the qui vive
occurred in a corpus of books?
(source:
Google Ngram Viewer
)