彼は内弁慶だ。

彼は内弁慶だ。

He is a lion at home and a mouse outside.

彼(かれ)は内弁慶(うちべんけい)だ。

Kare wa uchibenkei da.

彼 (かれ)

he; him; his; boyfriend

は (は)

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

内弁慶 (うちべんけい)

braggart; someone haughty and boastful at home but meek and reserved outside; a man who is a lion at home and a mouse abroad

だ (だ)

be; is; indicates past or completed action; indicates light imperative

Readings: ヒ、かれ、かの、か.の

Meanings: he, that, the

Readings: ナイ、ダイ、うち

Meanings: inside, within, between, among, house, home

Readings: ベン、ヘン、かんむり、わきま.える、わ.ける、はなびら、あらそ.う

Meanings: valve, petal, braid, speech, dialect, discrimination, dispose of, distinguish, conical cap

Readings: ケイ、よろこ.び

Meanings: jubilation, congratulate, rejoice, be happy