In human
Humans are the only living species in the Homo genus...

s, shyness (also called diffidence) is a social psychology
Social psychology
Social psychology is the scientific study of how people's thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others. By this definition, scientific refers to the empirical method of investigation. The terms thoughts, feelings, and behaviors include all...

 term used to describe the feeling
Feeling is the nominalization of the verb to feel. The word was first used in the English language to describe the physical sensation of touch through either experience or perception. The word is also used to describe experiences, other than the physical sensation of touch, such as "a feeling of...

 of apprehension
Fear is a distressing negative sensation induced by a perceived threat. It is a basic survival mechanism occurring in response to a specific stimulus, such as pain or the threat of danger...

, lack of comfort
Discomfort may refer to:* Pain, an unpleasant sensation* Suffering, an experience of unpleasantness...

, or awkwardness
Awkwardness is an unpleasant feeling, which can often arise in tense atmospheres where one doesn't really know how to act or what to say. Awkward situations can possibly later cause a form of anxiety. TV sitcoms often feature awkward situations, where one character misinterprets another person's...

 experienced when a person is in proximity to, approaching, or being approached by other people, especially in new situations or with unfamiliar people. Shyness may come from genetic traits, the environment in which a person is raised and personal experiences. There are many degrees of shyness.

He was not handsome, and his manners required intimacy to make them pleasing. He was too diffident to do justice to himself; but when his natural shyness was overcome, his behaviour gave every indication of an open, affectionate heart.

Sense and Sensibility by Jane Austen, 1811.

He's not an asshole, he's just shy. I think you have shy/asshole confusion, my friend.

Larry David|Larry David from Curb Your Enthusiasm

Shyness is nice, and shyness can stop you from doing all the things in life you'd like to.

Morrissey in the The Smiths|Smiths song Ask