Definition of "backslap"

backslap

verb
third-person singular simple present backslaps, present participle backslapping, simple past and past participle backslapped
1. To enthusiastically affirm or congratulate a person, especially by patting them on the back.
  Quotations
  In public he put on a performance that was at once outraged and outrageous, but usually he did not carry grudges into his private life. Exuding the backslapping air of a socializer who loved to gamble and drink, he could not understand why people whose careers he had ruined and publicly ridiculed would be hostile to his friendly advances.
  1983 August 13, John Kyper, “Flamboyant Inquisitor”, in Gay Community News, volume 11, number 5, page 14