FROM STRONG’S HEBREW DICTIONARY (1890)

Strong’s Hebrew Dictionary (1890) — public domain, printed whole.

natsar naw-tsar' — a primitive root; to guard, in a good sense (to protect, maintain, obey, etc.) or a bad one (to conceal, etc.):-- besieged, hidden thing, keep(-er, -ing), monument, observe, preserve(-r), subtil, watcher(-man).