a.k.a Intertropical Convergence Zone (ICZ)
Early sailors named this belt of calm the doldrums because of the low spirits they found themselves in after days of no wind. To find oneself becalmed in this region could mean death in the era when wind was the only motive force available, and it was certainly a depressing experience to be isolated, in the middle of the ocean, in a hot, muggy climate.
The adjective form of the prepositional phrase "in the doldrums." It is used to express the definition of Doldrums (a dull, listless, depressedmood; low spirits) in an adjective form.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.