This Japanese four-character phrase (四字熟語) roughly means, “the range of human emotions.” Individually the characters mean…
喜 – happiness
怒 – anger
哀 – sorrow/pity (Love this kanji, it’s used in 哀れ. Very Japanese.)
楽 – pleasure
Together, these characters express the entire range of feelings that a person might have.
One example sentence using this expression is,
顔に喜怒哀楽を表さない (kao ni kidoairaku wo arawasanai), which means, “to not show emotion (on one’s face).
Demonstrating your knowledge of these expressions is one way to convince Japanese people that you really do know some Japanese. Memorize them!