Word Roots are a Part of History. "Histories Make Men Wise" -- Bacon.

genius

according to ancient Roman belief, a guardian spirit assigned to a person at his birth; extended further to mean great mental capacity and inventive ability in some art, science, etc.

天才, 高智力, 天赋

See also: genus means a class, kind. Please see also: genus

genius = gen (origin, race, kind 起源； 种族； 种类) + i -us (Latin noun suffix in singular masculine form 拉丁语名词单数阳性后缀);
genius = the natural ability of a person by birth 一个人出生时就拥有的能力;
genius = extended further to mean the great natural ability of a person by birth 一个人出生时就拥有非凡的能力
genius = 意为天才, 天赋

Note: You may sometimes find that a vowel such as o is often inserted between two roots, as o inserted between phon and graph in phonograph = phon + o + graph, the reason is for easy pronounciation. Another example is archaeology = archae + o + logy