godan verb (-ku), intransitive verb
Archaic intransitive verb meaning to perform worship or to enshrine a deity; used in classical Japanese and Shinto contexts. Not used in modern everyday speech.
古事記には、神を斎く場面が描かれている。
In the Kojiki, there are scenes depicting the worship of gods.
祀る is the common modern transitive verb for 'to enshrine' or 'to worship', while 斎く is an archaic intransitive verb with a similar meaning.
The exact derivation is uncertain; it is an old Japanese verb associated with Shinto purification and worship.