yǎn​xiàn

informer

眼线 (眼線) yǎn​xiàn
informer noun
a person who provides secret information, such as a spy, snitch, or scout

The police planted an informant within that criminal gang.

eye line noun
makeup applied around the eyes to enhance or define their shape

She is wearing very heavy eyeliner today.

Frequency

Movie subtitles
2.50 per million appears in 1% of films
Written text
6.15 per million

Sources

Definitions
CC-CEDICT