Emily Dickinson Lexicon

PEN'SIVE, a. [It. pensivo, pensieroso; Sp. pensativo; Fr. pensif, from penser, to think or reflect; L. penso, to weigh, to consider; pendo, to weigh.]

1. Literally, thoughtful; employed in serious study or reflection; but it often implies some degree of sorrow, anxiety, depression or gloom of mind; thoughtful and sad, or sorrowful. Anxious cares the pensive nymph oppress'd. – Pope.
2. Expressing thoughtfulness with sadness; as, pensive numbers; pensive strains. – Prior.