I hardly know her is a typical English humor phrase, said after words that are ending with –er or –re.
The idea is to interpret the word as a verb to be done to some woman.
– Can you give me the toaster?
-Toast her? I hardly know her.
The joke had been around for quite a while, so it is rather hard to determine the origin, where it comes from.
What is known, that it is a reoccurring jest in the world famous show; The Office, where Michael is often heard making the jest.
It appears in the 2007 episode, titled Safety Training, for example.
The pure badness of the pun made it spread far and wide, with many dad joke enthusiasts embracing it today.
Urban Dictionary had listed it to their wide array of entries already in 2008, though another definition had been written in 2011 as well.
In 2015, it even appeared on Reddit, as a user was inquiring about the meaning of the phrase “I hardly know her”.
- Urban Dictionary – I Hardly Know Her