What is indefinite pronouns?

Indefinite pronouns are pronouns used to refer people or things without indicating exactly who or what they are. They do not refer to specific person, place etc. It is often difficult or impossible to pin down a precise antecedent for an indefinite pronoun.

person object place
someone/somebody something somewhere
anyone/anybody anything anywhere
everyone/everybody everything everywhere
no one/nobody nothing nowhere

Other indefinite pronouns:
Most, all, another, any, few, many, several, each, none, both, each, neither, such, little

Indefinite pronouns are like other pronouns. They can stand alone as subject or object of a sentence.

Everybody has something to say.
(Everybody ~ subject, something ~ object)

When we use someone, anyone, everyone, each, either, one, no one, nobody, as a subject, it takes a singular verb.

Both, many, few, several – It takes plural verb.

Some indefinite pronouns, such as none, some, half, take a singular verb or a plural verb, depending on the meaning of the pronoun or noun which follows.

Some of the sugar was spilled on the floor.
Some of the apples were spilled on the floor.

Half the money is yours.
Half of the students were absent.

Indefinite pronouns, unlike personal pronouns, do not vary their form. (Compare: I, me, my, mine) There is just one exception: pronouns ending in -one and –body can have the possessive ending ‘s.

Everyone’s life was in danger.
For further details: http://www.englishclub.com/grammar/pronouns-indefinite.htm http://www.infoplease.com/cig/grammar-style/indefinite-pronouns.html

Whether long explanation or not:-
A pronoun is used instead of a noun to refer to someone or something.eg:-she,something,and myself.
Indefinite pronoun:- is a pronoun such as "someone","anything",or" nobody", which you use to refer in a general way to a person without saying who or what they are,or what kind of person or thing you mean.
eg:-Yung xx is the someone I love,and nobody else and I pay anything for her marriage!
Personal pronoun:- is a pronoun such as "I","you","she", or "they" which used refer to speaker or hearer, or to a person whose identity is clear,usually because they have already been mentioned.
eg.:-As a job,"she" is a singer.
Reflexive pronoun:-is a pronoun such as "myself" which refers back to the subject of a sentence or clause.
eg:-I,myself,love her very much!
Relative pronoun:-is a word such as "who","which",or "that",----that is used to introduce a relative clause.eg:-The girl,who came here yesterday,was called Joey.
"Whose"",when"," where", and "why" are generally called relative pronouns,though they are actually adverbs.