1.Definition: (used of metals) consisting of or alloyed with inferior metal
"Base coins of aluminum", "A base metal"
2.Definition: debased; not genuine
"An attempt to eliminate the base coinage"
3.Definition: having or showing an ignoble lack of honor or morality
"That liberal obedience without which your army would be a base rabble"
5.Definition: not adhering to ethical or moral principles
"Base and unpatriotic motives", "A base, degrading way of life"
6.Definition: of low birth or station (`base' is archaic in this sense)
"Baseborn wretches with dirty faces"
7.Definition: serving as or forming a base
"The painter applied a base coat followed by two finishing coats"