Writing Definition

Discipline

“In its original sense, discipline is referred to systematic instruction given to disciples to train them as students in a craft or trade, or to follow a particular code of conduct or "order".”
-http://en.wikipedia.org/wiki/Discipline

In other words, discipline is simply an act of training somebody to abide a particular code of conduct by giving set(s) of instruction(s). Discipline may come in different methods. Military discipline involves regulating the morale of the members of any military by sending them to military trainings to correct, mold and perfect the mental and moral their characters. Child discipline involves teaching children how to act correctly in different situations. Self-discipline involves motivating oneself in spite of negative emotions and thoughts.

Accountability

“Accountability is the concept in ethics and governance with several meanings. It is often used synonymously with such concepts as responsibility, answerability, blameworthiness, liability, and other terms associated with the expectation of account-giving. As an aspect of governance, it has been central to discussions related to problems in the public sector, nonprofit and private (corporate) worlds. In leadership roles, accountability is the acknowledgment and assumption of responsibility for actions, products, decisions, and policies including the administration, governance, and implementation within the scope of the role or employment position and encompassing the obligation to report, explain and be answerable for resulting consequences.”
-http://en.wikipedia.org/wiki/Accountability


In short, accountability is a concept in ethics and governance that may mean different things, but basically, it is the obligation of an individual or organization to account for its activities, accept responsibility for them and to discuss and present results in a transparent manner. It also includes the responsibility concerning money or other entrusted property.

Maturity

"Maturity is a psychological term used to indicate how a person responds to the circumstances or environment in an appropriate manner. This response is generally learned rather than instinctive, and is not determined by one's age. Maturity also encompasses being aware of the correct time and place to behave and knowing when to act appropriately, according to the situation and the culture of the society one lives in."
- http://en.wikipedia.org/wiki/Maturity_(psychological)

In other words, maturity is the stage where a person can handle things/problems and deal with other people. Being a matured person does not only talks about a person's ideal behaviors, it also tackles about how a person do what is appropriate that will lead to a right decisions. Maturity may be about adulthood, sexual maturity, and maturity in terms of finance.