tripping

Could you please help me to understand the word "tripping" that I found in a book by NoViolet Bulawayo whose title is We Need New Names?
The word is part of a list of typical American words.
Here it is:
pretty good, for real, awesome, totally, skinny, dude, freaking, bizarre, psyched, messed up, like, tripping, clearance, allowance, douche bag, you’re welcome, acting up, yikes. The words whose meaning is not so clear to me are: tripping, clearance, allowance.

I hope you can give me a clue. Thank you very much.

Thanks a lot, anyway. The problem is I cannot really provide any more context, because even in the book it is just a list of American words that she (the main character) keeps under the tongue like talismans (that is what she actually says) to use when she needs them. So I thought they must be typical American words, i.e. American slang or colloquial American English, and I thought that maybe a native speaker would immediately have an idea of their meaning. I looked in more than one dictionary and I probably got quite close to what they mean, but one never knows. But thanks again, really.

Just a guess: Because "tripping" follows closely after "messed up", it might be definition 6 for "trip" as a verb in the WRF dictionary.

6. (intransitive) informal to experience the effects of LSD or any other hallucinogenic drug

I have no ideas about why "clearance" and "allowance" belong to the same list.

Thank you for the guess, srk. Very useful.