reverie

haaveilu puhekieltä A caper, a frolic; merriment.
A state of dreaming while awake; a loose or irregular train of thought; musing or meditation; daydream.
1847, Alfred Tennyson, The Princess, Canto VII, lines 107-108

we sat / But spoke not, rapt in nameless reverie, (..)

If the minds of men were laid open, we should see but little difference between that of the wise man and that of the fool; there are infinite reveries and numberless extravagancies pass through both.