(Christianity) Father, person of the Holy Trinity / (Christianity) Father, title for priests

father (parent) / father (clergyman) / Sr. (senior) (postnomial title used to indicate a father that shares the same name as the son)

(colloquial) old chap

founding father (man who founded something)

bogeyman (especially one who accompanies Father Christmas and threatens naughty children with a whip)

father superior (friar or monk in charge of a monastery)

grandfather

a father-in-law, the father of one's spouse / a stepfather, stepdad, the present husband of the mother of a child from a previous marriage

Father Christmas; Santa Claus

In French culture, a traditional Yuletide character, who accompanies Saint Nicholas and punishes naughty children