This is the 826th most frequent Icelandic word.
fundið
"Fundið" means "found" in English.
Here, 'fundið' is the neuter past participle form of 'finna', meaning 'to find', and indicates a completed action.
Ég hef fundið lykilinn.
I have found the key.
In this sentence, 'fundið' retains its function as the past participle of 'finna', now referring to the discovery of something humorous.
Þetta er eitt af fyndnustu grínatriðunum sem ég hef fundið.
This is one of the funniest jokes I have found.
Here, 'fundið' is used in the context of 'finna upp', meaning 'to invent', and describes the creation of something new.