Metalloid

n.	1.	Formerly, the metallic base of a fixed alkali, or alkaline earth; - applied by Sir Humphrey Davy to sodium, potassium, and some other metallic substances whose metallic character was supposed to be not well defined.
a.	1.	Having the appearance of a metal.
	2.	(Chem.) Having the properties of a nonmetal; nonmetallic; acid; negative.

Adj.

1.

metalloid - of or being a nonmetallic element that has some of the properties of metal; "arsenic is a metalloid element"

nonmetal, nonmetallic