I know him well.

I Pronoun

— The person who is speaking or writing I am writing this, and you are reading it.

I Noun

— The ninth letter or the alphabet; previous H, next J. I is a vowel.

I Symbol

— A symbol meaning first, as in "George I" (which is said as "George the first"). — The symbol for iodine on the periodic table of elements. — The symbol for electrical current.

I Number

— This is the roman numeral for one (1). It may be written as I or i.

i Noun

— The ninth letter or the alphabet; previous H, next J. I is a vowel.

know Verb

— When you know something, you have facts or ideas in your mind. I knew more things after I went to school. I know a little Spanish. I think I can do it, but I don't know. — You know a person, if you have met him or her. Yes, I know John. I met him in class last week. We want you to know that it will be OK.

him Pronoun

— he when used after a preposition or as the object of a verb. Give it to him (after preposition) She wrote him a letter (indirect object) She treated him for a cold (direct object)

well Adverb

— In a good way. He washed the table very well, so now it is very clean.

well Noun

— A hole in the ground for getting water or oil. There was no river nearby, so they dug a well to get water.