1. Vigilant
   "on guard against con artists"
   - on one's guard, upon one's guard, on your guard

See also: wary

• thyme
• thyme camphor
• thyme-leaved sandwort
• thyme-leaved speedwell
• Thymelaeaceae
• Thymelaeales
• thymic
• thymic acid
• thymidine
• thymine
• thymol
• thymosin
• thymus
• thymus gland
• Thymus serpyllum
• Thymus vulgaris
• thymy
• Thyreophora
• thyreophoran
• thyristor
• thyrocalcitonin
• thyroglobulin
• thyroid
• thyroid cartilage
• thyroid gland