Thoughtful, sober, or sad; employed in serious reflection; given to, or favorable to, earnest or melancholy musing.

Expressing or suggesting thoughtfulness with sadness; as, pensive numbers.

persistently or morbidly thoughtful

Pensive, a bright chestnut thoroughbred racehorse, came, in 1944, closer than any other horse at the time to the Triple Crown of Thoroughbred Racing. He was also the first to win the first two legs and then lose the third.