Flaws

Noun
flaw (plural flaws)

A crack or breach, a gap or fissure; a defect of continuity or cohesion.

A defect, fault, or imperfection, especially one that is hidden.

A defect or error in a contract or other document which may make the document invalid.

in Wiktionary

"I think people who have faults are a lot more interesting than people who are perfect."
(Spike Lee)

A character flaw is a limitation, imperfection, problem, phobia, or deficiency present in a character who may be otherwise very functional. The flaw can be a problem that directly affects the character's actions and abilities, such as a violent temper. Alternatively, it can be a simple foible or personality defect, which affects the character's motives and social interactions, but little else.
Flaws can add depth and humanity to the characters in a narrative. For example, the sheriff with a gambling addiction, the action hero who is afraid of heights, or a lead in a romantic comedy who must overcome his insecurity regarding male pattern baldness are all characters whose flaws help provide dimension. Perhaps the most widely cited and classic of character flaws is Achilles' famous heel.
In general, flaws can be categorized as minor, major, or tragic.

A minor character flaw is an imperfection which serves to distinguish the character in the mind of the reader / viewer / player / listener, making them memorable and individual, but otherwise does not affect the story in any way.
Examples of this could include a noticeable scar, a thick accent or a habit such as cracking their knuckles.
Protagonists and other major characters may (and usually do) have multiple minor flaws, making them more accessible, and enabling the reader / viewer / listener to relate to the character (in the case of a sympathetic character) or otherwise influence the audience's opinions of the character.
Many insignificant or archetypal characters which are encountered only once or rarely are defined solely by a single minor flaw, differentiating them from the stock character or archetype that they adhere to.

A major character flaw is a much more noticeable and important hindrance which actually impairs the individual, whether physically, mentally or morally. Sometimes major flaws are not actually negative per se (such as devout religious beliefs or a rigid code of honour), but are classified as such in that they often serve to hinder or restrict the character in some way.
Examples of this type of flaw could include blindness, amnesia or greed.
Unlike minor flaws, major flaws are almost invariably important to either the character's personal development or the story as a whole.
For villains, their major flaw is usually the cause of their eventual downfall.
For heroes, their major flaw usually must be overcome (either temporarily or permanently) at some point in the story, often at the climax, by their own determination or skill.
For neutral characters, or those that shift allegiance, the major flaw is usually the cause of either their corruption, redemption or both.
For the protagonist himself, his most visible flaw generally serves a more vital interest, as well, as it defines his or her core problem. It is the protagonist's reluctant (and usually unconscious) journey to address this problem that forms the spine of the story, sometimes acting as the MacGuffin to stimulate the plot.

in Wikipedia

"Faults are beauties in a lover's eye."
(Theocritus)

Fault

They came to tell your faults to me,
They named them over one by one;
I laughed aloud when they were done,
I knew them all so well before, --
Oh, they were blind, too blind to see
Your faults had made me love you more.

Sara Teasdale