Inferiority is the state of being not as good as someone or something else — or the feeling that you are not as good. A cheap tool can have inferiority in quality: it really is weaker. A person can feel inferiority: “I am less than other people.” In psychology talk, an “inferiority complex” is a deep, lasting feeling of being less than others, even when that is not fair or true. The word is formal. In everyday English people more often say “this one is not as good” or “I feel worse than them.” Though actually, the same word covers both a real gap (this product is weaker) and a feeling in the mind that may not match the facts.