foggy

Etymology

From fog + -y, originally in the sense "covered with tall grass; marshy; thick". It is not clear whether fog (“mist”) is a back-formation from foggy (“covered with tall, obscuring grass”) or has a separate Germanic origin, and hence whether foggy (“covered with tall grass”) and foggy (“obscured by mist”) represent one word or two. See fog ("mist"; "tall grass") for more.

adj

1. Obscured by mist or fog; unclear; hazy
2. (figurative) Confused, befuddled, etc.
   He was still foggy with sleep.
   If she knew [a psychiatrist was] observing her son with a view to finding out if he was foggy between the ears, there would be umbrage on her part, or even dudgeon. 1960, P. G. Wodehouse, Jeeves in the Offing, chapter VI
3. Being, covered with, or pertaining to fog (“tall grass etc that grows after, or is left after, cutting; moss”)
   For they will feed on foggy grass and such like. Also ye shall understand that horses and Cattel may not well be foddered in Winter all together, but […] 1680, Leonard Mascall, The government of cattel. Divided into three books, etc, page 221
   […] for as he shuts up his meadow at Christmas, leaves such foggy grass behind, and manures well, in case a wet hot summer succeeds, […] 1772, William Ellis, Husbandry, abriged, page 98
   See swingin' owr the foggy swaird, Begrac'd wi' angel features, […] 1808, John Stagg, Miscellaneous Poems, Some of which are in the Cumberland and Scottish Dialects, page 143