More generally: full of thought; meditative, reflective.

Engaged in or characterized by contemplation or thoughtful reflection. Obsolete.

Given to or characterized by meditation; contemplative, thoughtful, dreamy.

That engages in contemplation; (also) of or characterized by contemplation; meditative; contemplative.

That reflects or is reflected; reflective. Cf. reflecting, adj. Obsolete.

Absorbed or engrossed in thought, contemplation, etc. Also in earlier use with up.

Absorbed in thought; thoughtful, pensive.

= cogitabund, adj.

Meditating. (In quots. 1631 and 1802 used as postmodifier, perhaps in humorous imitation of the language of heraldry.) poetic in later use.

That meditates; characterized by meditation. Also in extended use.

Musing, meditating, thoughtful, deep in thought.

Absorbed in meditation. (In quot. humorously pedantic.)

With adjectives, as thoughtful-browed, thoughtful-faced, thoughtful-looking, etc.