wú​xiè​kě​jī

impeccable

无懈可击 (無懈可擊) wú​xiè​kě​jī
impeccable idiom
impossible to fault; flawless and without any weak points in an argument, defense, or performance

His logic is very tight, practically flawless.

Frequency

Movie subtitles
2.35 per million appears in 1% of films
Written text
1.22 per million

Sources

Definitions
CC-CEDICT