1. Vigilant
   - on guard, on one's guard, on your guard

See also: wary

• argufy
• arguing
• argument
• argumentation
• argumentative
• argumentatively
• Argun
• Argun River
• argus
• argus pheasant
• argus-eyed
• Argusianus
• argy-bargy
• argyle
• argyll
• Argynnis
• Argyranthemum
• Argyranthemum frutescens
• Argyreia
• argyrodite
• Argyrol
• Argyrotaenia
• Argyrotaenia citrana
• Argyroxiphium
• Argyroxiphium sandwicense