cogitabund
Deep in thought; meditative, thoughtful.
archaic, literary
To turn the apple of the eye towards the Nose, is their peculiar action who are Sowre and Severe; for, such are of a Contuitive, Grave, and Cogitabund aspect, such as is seen in those who with some Tragicall and Goblin-like look would affright and scare others.
Where it comes from
Learned borrowing from Latin cōgitābundus (“thinking, thoughtful”), from cōgitō (“to think; to consider, ponder; to intend, plan”) + -bundus (suffix forming adjectives with an active or transitive meaning). Cōgitō is derived from con- (prefix indicating a bringing together of several things) + agitō (“to put in motion; to rouse, stir up; to consider, meditate upon; to contrive, intend; to deliberate upon, discuss”) (from agō (“to act, do; to impel, move; to deliberate, discuss; to think upon”), ultimately from Proto-Indo-European *h₂eǵ- (“to drive”)) + -itō (suffix forming frequentative verbs)).
Adapted from the Wiktionary entry cogitabund (CC BY-SA 4.0).