1400 am I still a beginner?

It's not, but that hasn't stopped scores of other people. Do what you like.

Yes and no. Compared to a 1000 you're an expert and compared to a 2000 you're still a beginner.

Congrats on reaching 1400.

That reminds me of this thread of a 1200 blitz, 1400 rapid player VladimirHerceg91 https://www.chess.com/forum/view/general/the-curious-case-of-1200-the-expert-s-rating?page=1

Rating is all relational, but I wouldn't consider you a "beginner" - perhaps "learning" like the rest of us, but I'd say 1400 is more intermediate player level. This rating on chess.com certainly knows a few basic checkmates, theoretical endgames and is for the most part past opening principles and hanging pieces. 

In the tougher rating pools, then sure 1400 might be lower, but for the rating pool of ALL chess players, then 1400 is actually above average - tough to consider above the 50 percentile a "beginner"

300 is beginner

Congrats. Beginner is a relative - since everybody starts with a different skill level, when starting to play chess. Some people more or less immediately beat 1800s in longer time formats (once they've learned the rules). The same people will probably lose a lot in the quick / flagging / trickery - type of games. I don't know what the base skill level of the average player is, but I'd guess that it's below 1400 rapid.

Yes.

1400 is around the 95th percentile on this website. Fewer than one in twenty players here reach 1500. No one is claiming that this is approaching mastery, but I think that's setting the bar for beginner extraordinarily high. 

If not, then is there a forum "For Intermediates"?

depends

Compared to a grandmaster: beginner

Compared to average chess players: not a beginner

OK, once more:

If you just began, you are a beginner.

If you have been playing for years, you just stopped improving and have hit a plateau.

1400 is your puzzle rating. Your game rating is considerably lower, and definitely in the "beginner" range. 

My puzzle rating is 2300 what are you talking about?

Chuck Norris invented chess when he punched a tile floor, sending a shockwave to the center of the Earth's iron core, the antipodal force of which sent magma and molten metal oozing back up through the ground where he stood. From this crucible, Chuck Norris sculpted the game's 32 pieces with his bare hands before they were able to cool and harden, then placed them back on a small segment of tile floor that he had not earlier destroyed through that singular display of his raw physical power. A moment later, Chuck Norris simultaneously invented and mastered the game that we now play in its modern form. 

1400 online is on the verge of being intermediate. So keep it up, and get to a steady 1500. After that, chess starts.

Also keep in mind that your OTB rating will be 300-400 points lower, so you're still just at 1000-1100 in the real chess world. Stay humble, keep learning.