used before a noun to talk about a person, thing, or time that is close to you or that you have just mentioned
This book is very interesting.
I can't finish this report today.
✦ Old English this, neuter nominative and accusative singular of thes (“this”), from Proto-Germanic *þesi.
used to refer to a person, thing, situation, or idea that is close, happening now, or just mentioned
This is my sister, Anna.
Taste this and tell me if it's sweet enough.
✦ Same origin as the determiner sense, from Old English this
used before an adjective or adverb to show the exact degree or amount
I didn't think the mountain was this high.
Why are you driving this fast on a small road?
✦ Extension of demonstrative sense to degree usage, first recorded in Middle English.
used especially online to show strong agreement with what someone has just said or written
When the teacher said phones should stay in bags, several students whispered "This!"
Someone wrote "This!" under the post calling for shorter meetings.
✦ Slang extension of the pronoun, popularized in internet culture in the early 2000s.
