Politeness maxims (Geoffrey Leech)

politeness theory, which elaborates terms such as "positive politeness" and "negative politeness"

Register (sociolinguistics)

Valediction, expression used to say farewell (e.g. to end a letter) or the act of saying parting

image politeness

define politeness

wikipedia politeness

weblio politeness

kotobank politeness

jisho politeness