Dutch word for acorn. Also used to describe the head of a man's penis, but most commonly used to insult a man.
When used as an insult the most literal English translation for eikel would be 'dickhead' and is used in pretty much the same way.

A person with an outwardly dominant, masculine, or aggressive personality, but who also enthusiastically takes on the submissive or "bottom" role in the bedroom.

Dutch word for a seed that grows on oak trees, slang for the head of a mans dick