The term "dilf" is a slang abbreviation that stands for "Dad I'd Like to Friend" (often interpreted as an adult man who is attractive and has children). It is typically used in a humorous or lighthearted context and often refers to an older man who is perceived as being appealing or desirable.
"DILF" is a portmanteau of the term "dad" and the slang acronym "I’d Like to Friend," which plays off of similar terms such as "MILF," famously meaning "Mom I'd Like to Friend." The term has emerged from internet culture and dating slang.