Adjectives

(a)reflectivecapable of physically reflecting light or sound“a reflective surface”
(s)brooding, broody, contemplative, meditative, musing, pensive, pondering, reflective, ruminativedeeply or seriously thoughtful“Byron lives on not only in his poetry, but also in his creation of the `Byronic hero' - the persona of a brooding melancholy young man”
(s)reflectivedevoted to matters of the mind“the reflective type”