He 'took the Fifth' [=he refused to answer] when his wife asked him where he'd spent the night.
He felt more and more like a 'fifth wheel' at the office.
She donated a 'fifth' of her income to charity.
(..) Stay out of my freezer! Ever since she walked out on me, I, uh... What?..... What, you wanna spell it out with noodles? No, it's, it's more of a fifth date kinda revelation. Oh, so there is gonna be a fifth date? Isn't there? Yeah... yeah, I think there is. -What were you gonna say? ...Sexually. - Um... how long? - Two years. Wow! I'm-I'm-I'm glad you smashed her watch! So you still think you, um... might want that fifth date? ...Yeah. Yeah, I do. We are gathered here today to join Joanne Louise Cunningham and Charles, Chachi-Chachi-Chachi, Arcola in the bound of holy matrimony. (..)1994 TvShow: Friends Title: The One Where Monica Gets a Roommate Season: 1 Episode 1