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

See also: wary

• explosion
• explosive
• explosive charge
• explosive compound
• explosive detection system
• explosive device
• explosive mixture
• explosive trace detection
• explosive unit
• explosively
• explosiveness
• expo
• exponent
• exponential
• exponential curve
• exponential decay
• exponential equation
• exponential expression
• exponential function
• exponential return
• exponential series
• exponentially
• exponentiation
• export
• export credit