the conscious subjective aspect of feeling or emotion
"Her grief was not just a reaction to the news, but a profound affect that lingered in her silence for days."
One's mood or inclination; mental state.
"Her cheerful demeanor began to affect me after just a few minutes of talking."
In plain English: An affect is an emotion or feeling that someone experiences.
"The weather did not affect our mood, so we decided to go for a walk."
Usage: Use "affect" as a noun only in specific psychological contexts to describe an observable emotional response or display, such as a flat affect. In everyday conversation, people almost always mean the verb "to influence" when they say this word.
To influence or alter.
"He tried to affect indifference when he walked past the room where his favorite team had just won."
To make a show of; to put on a pretense of; to feign; to assume. To make a false display of.
In plain English: To affect something means to have an influence on it or cause a change in how it is.
"The bad weather affected our plans for the picnic."
Usage: Use affect as a verb when you mean to pretend to feel an emotion or display a false feeling, such as affecting sadness to gain sympathy. This usage is distinct from the more common meaning of influencing something or causing a change.
The word "affect" entered English via Middle English and Old French from the Latin afficere, which literally meant "to make" or "do." Originally, it described the act of acting upon someone to influence them or attack with disease.