kè​xīng

ill-matched

克星 (剋星) kè​xīng
ill-matched noun
fated by destiny or astrology to be incompatible or to bring misfortune to another

Superstitious people believe he is destined to be that person's nemesis.

nemesis noun
a person or thing that is a constant source of ruin or defeat; a bane

This new antibiotic is the nemesis of drug-resistant bacteria.

Frequency

Movie subtitles
1.49 per million appears in 1% of films
Written text
2.33 per million

Sources

Definitions
CC-CEDICT