惕

怵惕

chù tì

to be alarmed

惕然

tì rán

to be afraid, fearful of

惊惕

jīng tì

to be alarmed

朝乾夕惕

zhāo qián xī tì

cautious and diligent all day long (idiom)

警惕

jǐng tì

to be on the alert

警惕性

jǐng tì xìng

vigilance