adj. 25B6; adjective
I felt very lonely : ISOLATED, alone, friendless, with no one to turn to, forsaken, abandoned, rejected, unloved, unwanted; N. Amer. lonesome.
the lonely life of a writer : SOLITARY, unaccompanied, lone, by oneself/itself, companionless.
a lonely road : DESERTED, uninhabited, unfrequented, unpopulated, desolate, isolated, remote, out of the way, secluded, off the beaten track, in the back of beyond, godforsaken; informal in the middle of nowhere.
popular, sociable, crowded.