Translation:He is often angry.
@ DJ Jammur -- Take a look at the Wikipedia article on Chinese Adjectives, particularly the section with the headings Predicative (after nouns) & First Pattern: Unlike English, subjects and predicates adjectives in a Chinese sentence are not linked by copula but by degree adverbs, such as 很 hěn "very," 好 hǎo "highly," 真 zhēn "really," and 非常 fēicháng "extraordinarily, extremely."
Because you have to have a degree adverb to accompany a free-standing, affirmative, predicate adjective, the most basic level of these, 很, can basically be ignored in this structure.
Nothing in the previous post is mixed up, that's the beauty of the Chinese language. Maybe you'll learn to appreciate it or maybe you'll find it intolerable. Anyway by not aiming to be very precise it leaves a lot of room for the meaning derived from context or feeling. It is thus much more comprehensive and inclusive. Also, takes longer to learn and understand.