UW is distinctly different from FID and COIN, as Old Eagle mentioned, although it can occur within other operations. My spin is below.

UW is a special operations mission. UW is a broad spectrum of military and paramilitary operations normally of long duration and conducted by, with, and through indigenous or surrogate forces. These surrogate forces are organized, trained, equipped, supported, and directed in varying degrees by an external source. UW activities include, but are not limited to, insurgency, guerrilla warfare, subversion, sabotage, intelligence, PSYOP, and unconventional assisted recovery. UW most frequently refers to the military and paramilitary aspects of an insurgency designed to resist, overthrow, or gain political autonomy from an established government or used to resist or expel a foreign occupying power. However, UW can also refer to military and paramilitary support to an armed group seeking increased power and influence relative to its political rivals without overthrowing the central government and
in the absence of a foreign occupying power.