The basic meaning of קָדוֹשׁ is “set apart for Divine service.”  It’s opposite (antonym) would be חֹל (common, ordinary, profane), indicating things which are used for common purposes rather than sacred purposes.  To be holy (commanded in both “testaments”; see 1 Peter 1:13-16; 2 Peter 3:11; etc.), and it means to be set apart FROM the common, ordinary, worldly, and profane and to be set apart TO Hashem.