serious

The word “serious” means not joking or humorous; solemn in manner. In plain terms, grave or earnest — either in someone's manner, or describing something important or dangerous.

“Serious” is pronounced SEER-ree-uhs (/ˈsɪɚ.i.əs/ in IPA).

Here is “serious” used in a sentence: “He gave her a serious look and said nothing more.”

Words with a similar meaning to “serious” include austere, frightful, demure, grave, earnest and grievous.

The opposite of “serious” — its antonyms — are trifling, unimportant, jesting, gaudy and witty.

“Serious” is an adjective.

The word “serious” comes from Medieval Latin. From Old French serieux, from Medieval Latin sēriōsus, based on Latin sērius, "grave, earnest.".

“Serious” is a very common word in modern English, usually learned at around the B1 level.

The words overlap but differ in feel. Serious means not joking, being earnest and in earnest about something. Solemn adds a note of formal gravity or ceremony, the mood of a funeral or an oath. Someone can be serious in a casual chat, but solemn suggests a deeper, more dignified seriousness.

When serious means not joking, its opposites are playful, lighthearted, humorous, or flippant. A serious expression contrasts with a smiling or joking one. In the related sense of grave or important, the opposites shift to trivial, minor, or unimportant, showing how much the word depends on context.

Serious is neutral and takes its color from context. Calling someone a serious student is a compliment, suggesting dedication. Describing a mood as too serious can be mild criticism, implying a lack of fun. And a serious illness or serious mistake is clearly negative. Tone and setting decide the meaning.

A doctor delivering test results wears a serious expression, showing no trace of humor. A serious conversation is one held in earnest, not in jest. In each case the word marks a solemn, focused manner, the opposite of laughing, teasing, or treating a matter lightly.