Punch.

Tsuki (突き) is the Japanese word for "moon”, coming from the verb tsuku (突く), meaning "to thrust". The second syllable is accented, with Japanese's unvoiced vowels making it pronounced almost like "ski" (but preceded by a "t" sound). In Japanese martial arts and Okinawan martial arts, tsuki is used to refer to various thrusting techniques.

In karate and its variants, the term tsuki is used as a part of a compound word for any one of a variety of thrusting techniques (usually punches). It is never used as a stand-alone term to describe a discrete technique. For example, gyaku seiken chudan-tsuki, more commonly referred to as chudan-tsuki (段突), refers to a mid-level (chudan) punch (tsuki) executed with the rear (gyaku) arm. Note that in a compound word, where tsuki does not come first, its pronunciation and writing changes slightly due to rendaku, and it is pronounced as "zuki" (and is sometimes transliterated that way).