noun - a substance or material that allows electricity to pass through it under some conditions but not under others, used especially in electronic devices
adjective, formal - matching something in size, degree, or importance; appropriate in relation to something else
noun, technical - a serious mental condition in which a person gradually loses the ability to think, remember, and behave normally, usually because of disease or old age
adjective, formal - feeling very sad and lonely because something important has been taken away, or lacking something you need or expect
noun, formal - an action or process that shows you regret hurting someone or doing something bad, and try to make it better