"Unrequited" is the sixteenth episode of the fourth season of The X-Files. The mysterious assassination of a high-ranking military official has Mulder and Scully racing against the clock to stop a seemingly unstoppable - and invisible - assassin. Text taken from the Unrequited summary http://en.wikipedia.org/wiki/List_of_The_X-Files_episodes#Season_4:_1996-1997 here.

"not requited: not reciprocated or returned in kind unrequited love."

not returned in kind; "unrequited (unanswered) love"

Unrequited is the fifth album from Loudon Wainwright III. It was his last album on the Columbia Records label, released in 1975. Tracks 1-7 were recorded in a studio, while tracks 8-14 were recorded live at the Bottom Line in New York City.

To present participles which come from intransitive verbs, or are themselves employed as adjectives, to mark the absence of the activity, disposition, or condition implied by the participle;