What does nincha mean?

Answer 1

If you meant Ninja - an explanation follows. Could not find the word you used.

The short answer for what Ninja means is "one skilled in the art of stealth." Here is more information about the meaning of the word.

Ninja is the on'yomi reading of the two kanji 忍者 used to write shinobi-no-mono (忍の者), which is the native Japanese word for people who practice ninjutsu (忍術, sometimes erroneously transliterated as ninjitsu). The words: ninja and shinobi-no-mono, along with shinobi, another variant; became popular in the post-World War II culture[citation needed]. The term shinobi (historically sino2bi2 written with the Man'yōgana 志能備), has been traced as far back as the late 8th century when Heguri Uji no Iratsume wrote a poem[1] [2] to Ōtomo no Yakamochi. The underlying connotation of shinobi (忍), in Sino-Japanese means "to steal away" and—by extension—"to forbear," hence its association with stealth and invisibility. Mono (者, likewise pronounced sha or ja) means "person." The nin of ninjutsu is the same as that in ninja, whereas jutsu (術) means skill or art, so ninjutsu means "the skill of going unperceived" or "the art of stealth"; hence, ninja and shinobi-no-mono (as well as shinobi) may be translated as "one skilled in the art of stealth." Similarly, the pre-war word ninjutsu-zukai means "one who uses the art of remaining unperceived."

Answer 2

Do you mean ninja? Someone expertly trained in the martial arts who is an assassin? If not, I'm not sure that it means.