stage fright

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Acute nervousness associated with performing or speaking before an audience.

from The Century Dictionary.

• noun Nervousness experienced on facing an audience, especially for the first time.

from the GNU version of the Collaborative International Dictionary of English.

• Nervousness felt before an audience.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun uncountable A state of nervousness about performing some action in front of a group of people, on or off of a stage; nerves; uncertainty; a lack of self-assurance before an audience.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun fear that affects a person about to face an audience