What does "unnecessary" mean?

1. (not needed) not needed or required in a particular situation. 2. (excessive or uncalled for) more than what is fair or needed, often used for things that are annoying or rude.

Is it correct to say "It is unnecessary for you doing that."?

No — say "It is unnecessary for you to do that.". The adjective 'unnecessary' is followed by an infinitive (to do), not a gerund (doing).

unnecessary

adj.

US //ənˈnɛsəˌsɛɹi// UK //ʌnnˈɛsəsəɹi// un·nec·es·sary

1 not needed (adj.)
B1 Intermediate

not needed or required in a particular situation.

not essential or required; redundant to the primary objective.

Example

The extra explanation was unnecessary because everyone already understood the plan.

Example

The manager decided that the additional safety briefing was unnecessary given the team's extensive experience with the machinery.
Pitfall

It is unnecessary for you doing that.

It is unnecessary for you to do that.

The adjective 'unnecessary' is followed by an infinitive (to do), not a gerund (doing).
2 excessive or uncalled for (adj.)
B2 Upper Intermediate

more than what is fair or needed, often used for things that are annoying or rude.

exceeding what is appropriate or justifiable; often used to describe excessive force, rudeness, or complexity.

Example

His rude comment about her hair was completely unnecessary.

Example

The referee penalised the player for an unnecessary tackle that occurred well after the whistle had blown.
- excessive
- uncalled for
- gratuitous
- justified
- appropriate

Origin

From un- + necessary.

Word family

Adjectiveunnecessary
Adverbunnecessarily