vagarist
One whose thought wanders in many directions.
The men who call themselves philosophers, may look with pride upon their speculations; but true philosophy is nothing more than the art of being happy; and a woman contented to cull the flowers of the moment, in the modest vale of female enjoyments, has more true philosophy than the vagarist, who loses his way to bliss in wandering through the clouds, or who, madman like, hazards life, happiness, every thing, for a bubble, or for a name.
Where it comes from
From Latin vagus (“wandering”) + -ist. By surface analysis, Latin vag(us) + -arist.
Adapted from the Wiktionary entry vagarist (CC BY-SA 4.0).