adjective
archaic
ar-KAY-ik/ɑːrˈkeɪɪk/
Belonging to an earlier time and no longer in general use.
The archaic telephone stands beside a small modern smartphone.

Etymology
Arkhaios meant “ancient” or “old-fashioned,” ultimately invoking a beginning or origin. Archaic applies that connection with an earlier age to things that are very old or have fallen out of ordinary use.
In context
now of course the bhagavad-gita is in sanskrit but he makes his own translation and he's deliberately trying to make this sound archaic because the gita is very old
More examples
- The poem uses archaic words like “thou” and “hath.”
- That archaic law is no longer enforced.
- We replaced the archaic filing system with a searchable database.
Forms
archaic
archaism noun — An old-fashioned word, expression, or practice.
Similar words
- obsolete
- Obsolete emphasizes replacement or loss of practical usefulness.
- antiquated
- Antiquated emphasizes being outdated and unsuitable for current needs.
- old-fashioned
- Old-fashioned can describe styles still used despite their age.