This week’s adjective is “uptight”, and native English speakers use this word to describe a person who is not flexible at all especially when it comes to following rules. These people are usually very serious and have no sense of humor. For example:
My new boss is so uptight about the dress code. He makes all the men wear a jacket and tie even in the summer!
A: We can’t leave until 6:00, and it’s only 5:57!
B: Don’t be so uptight! It’s only three minutes!
My parents have gotten really uptight since they retired. They used to be really fun and open-minded, but now they seem to disapprove of everything I do.
We have a new supervisor coming in, and I’ve heard he’s really uptight! I’m not looking forward to working with him!
Obviously this word is very negative, so we don’t usually use it to describe ourselves. Also, we don’t usually say it directly to another person. Therefore, it’s very rude to say “You are so uptight.” to another person; however, sometimes we say “Don’t be so uptight!” as in my second example. Please note that you should only say this to close friends but never to someone of higher status than you.
English Help Online's Blog 
misa Said:
on June 22, 2011 at 3:10 pm
Hello.
Dose “uptight” mean too serious or punctillous?
Is it fifferent from stubborn?
This word “uptight” looks a little difficult to use.
I have to be careful about using it.
englishhelponline Said:
on June 22, 2011 at 4:47 pm
The word “uptight” means being too rigid about details and rules. The opposite of it is “relaxed” or “flexible”. The word “stubborn” means someone
who refuses to change their thinking about something, so “uptight” has a slightly different focus.
I hope that helps.
Mike