手瓜硬 [－－－]

Jyutping sau2 gwaa1 ngaang6
Pinyin shǒu guā yìng

Definitions (CC-CANTO)

(slang) to describe someone (or an organization) who has tremendous power or authority (literally "muscular elbow")

Definitions (粵典–words.hk)

Definitions (Kaifangcidian)