“CUBICS” is a valid word. — 12 points Scrabble

busa vehicle carrying many passengers; used for public transport
suba large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States
cuban awkward and inexperienced youth
sicurge to attack someone
bis
cisan alliance made up of states that had been Soviet Socialist Republics in the Soviet Union prior to its dissolution in Dec 1991
siba person's brother or sister

ishave the quality of being; (copula, used with an adjective or a predicate noun)
usNorth American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776
sia tetravalent nonmetallic element; next to oxygen it is the most abundant element in the earth's crust; occurs in clay and feldspar and granite and quartz and sand; used as a semiconductor in transistors
bia heavy brittle diamagnetic trivalent metallic element (resembles arsenic and antimony chemically); usually recovered as a by-product from ores of other metals

CUBICS