informal an older man who shows a strong and unpleasant interest in sex.
On the top shelf they've got all those horrible magazines for dirty old men.
dirty old man
An older man who is deliberately outspoken when it comes to sexual topics, to the point of making others uncomfortable. Bob is always making lewd comments to the younger women at work. He's such a dirty old man.
a ˌdirty old ˈman
(informal, disapproving) an older man who thinks too much about sex: Lots of dirty old men stood around looking at pornographic magazines.