From Proto-Slavic *kъsьnъ, of uncertain origin. Possibly from an earlier *kъtsьnъ with meaning spoiled, passed its deadline, related to Bulgarian кисна (kisna, “to soak, to ferment”). According to Al. T. Balan, from къ (k, “towards”) + сън (sǎn, “dream, sleep”).
See also къ́сно (kǎ́sno).
къ́сен • (kǎ́sen) (adverb къ́сно)
| masculine | feminine | neuter | plural | |
|---|---|---|---|---|
| indefinite | по́-къ́сен pó-kǎ́sen |
по́-къ́сна pó-kǎ́sna |
по́-къ́сно pó-kǎ́sno |
по́-къ́сни pó-kǎ́sni |
| definite (subject form) |
по́-къ́сният pó-kǎ́snijat |
по́-къ́сната pó-kǎ́snata |
по́-къ́сното pó-kǎ́snoto |
по́-къ́сните pó-kǎ́snite |
| definite (object form) |
по́-къ́сния pó-kǎ́snija |
| masculine | feminine | neuter | plural | |
|---|---|---|---|---|
| indefinite | на́й-къ́сен náj-kǎ́sen |
на́й-къ́сна náj-kǎ́sna |
на́й-къ́сно náj-kǎ́sno |
на́й-къ́сни náj-kǎ́sni |
| definite (subject form) |
на́й-къ́сният náj-kǎ́snijat |
на́й-къ́сната náj-kǎ́snata |
на́й-къ́сното náj-kǎ́snoto |
на́й-къ́сните náj-kǎ́snite |
| definite (object form) |
на́й-къ́сния náj-kǎ́snija |