A helmet is British slang word that's used to describe an individual who's being stupid or has completely no reputation to join a conversation or add their opinion.

From STEM, an abbreviation short for "Science, Technology, Engineering and Mathematics", a STEMlord is a pejorative term for a particular kind of person who has studied in these areas at university or works in these fields who holds a pretentious, condescending attitude to anyone who has studied in any other fields, particularly the Arts and Humanities. They typically believe themselves to be more "intelligent" and "rational", while generally remaining incredibly ignorant outside of their areas of expertise and having the charisma of a rotting pig's backside.

A helmet is someone who tries too hard and thinks they are proper top like they're on par with the head of a penis. Ironically however they are more like a skid mark on an old mans pair of gruds

The first meaning is another name for the head of the penis. Due to the similarity of shape and positioning on the end of the penis.

However you can also call someone a 'helmet'. You would use this if they are acting like a total idiot by saying or doing ridiculous things.

1. the top of a man's penis, or a hermaphodite's penis I guess as well. Also reffered to as a purple helmet.
2. A condom, as worn on the head of your penis, perhaps a more accurate term.
3. A kevlar, or plastic covering for your less important head, as worn while riding a motorcycle or visiting a construction site. Or oddly, enough, while exploring actual caverns. See spelunking.

To play the game of Helmet means to touch everything with the tip of your penis. i.e. - to go up to your friend's toothbrush and rub your penis tip on it. Gross? Yes. Amusing? Not really.

an individual who is in need of a helmet, for their mental capacity is so small that thoughts floating around can hurt their head, causing their brow to furrow. a slight tilting of the head is also common.