Intensifiers are adverbs or adverbial phrases that strengthen the meaning of other expressions and show emphasis. Words that we commonly use as intensifiers include absolutely, completely, extremely, highly, rather, really, so, too, totally, utterly, very:
She was so upset. I felt extremely sorry for her.
She has a very strict teacher.
Don’t work too hard. Sometimes you’ll get more done by relaxing a bit.
I don’t think she understood the topic and her essay was rather a mess.
She’s really offended her sister.