The second personal pronoun, in the singular number, denoting the person addressed; thyself; the pronoun which is used in addressing persons in the solemn or poetical style.(pronoun)
source: webster1913
verb (v)
To address as thou, esp. to do so in order to treat with insolent familiarity or contempt.(verb)
source: webster1913
To use the words thou and thee in discourse after the manner of the Friends.(verb)