I*de"al*ism (?), n. [Cf. F. idéalisme.]

1.

The quality or state of being ideal.

2.

Conception of the ideal; imagery.

3. (Philos.)

The system or theory that denies the existence of material bodies, and teaches that we have no rational grounds to believe in the reality of anything but ideas and their relations.

© [Webster 1913]

I*de"al*ism, n.

The practice or habit of giving or attributing ideal form or character to things; treatment of things in art or literature according to ideal standards or patterns; -- opposed to realism.

© [Webster 1913]

idealism (definition)