What word describes a manner that is marked by joking?

The term that captures a manner marked by joking is "jocular." This word directly relates to humor and is used to describe behavior that is playful, light-hearted, or characterized by jesting. Someone who is jocular often engages in amusing dialogue or actions, fostering a cheerful or relaxed atmosphere. Utilizing this word suggests a lively and engaging interaction, which contrasts sharply with more serious or somber dispositions.

In this context, "serious" and "solemn" denote attitudes that are serious or grave, lacking in humor and light-heartedness. Similarly, "morose" refers to a disposition that is sullen or gloomy, which is the antithesis of being joking or playful. Therefore, "jocular" is the appropriate choice as it accurately reflects a manner that embraces humor and levity.