gaydar

The story

1. Englishgay
2. Englishradiotelegraphyclip.
3. Englishradio
4. Latindētēctiō
5. Englishdetection
6. Proto-Indo-European*h₂ent-
7. Proto-Indo-European*h₂énts
8. Proto-Indo-European*h₂énti
9. Proto-Germanic*andi
10. Old Englishand
11. Middle Englishand
12. Englishand
13. Proto-Indo-European*(H)rek-
14. Proto-Celtic*reketi
15. Gaulish*rekosbor.?
16. Proto-Indo-European*h₃reǵ-
17. Proto-Germanic*rinkaną
18. Proto-Germanic*rankaz
19. Frankish*rankbor.?
20. Vulgar Latin*rencus
21. Old Frenchreng
22. Old Frenchrengier
23. Middle Englishrengen
24. Englishrange
25. Englishranging
26. EnglishRADAR
27. Englishradar
28. English todaygaydar

Blend of gay + radar, equivalent to gay + -dar.

First known use, by meaning

• from early 1980s The supposed ability to detect whether or not a person is gay by observing that person's appearance, mannerisms, etc.