不苟言笑[bù gǒu yán xiào]
词典reserved：预订的；矜持的；储藏着的。
词典serious in speech and manner：不苟言笑。
词典不苟言笑的解释
词典keep one's gravity：保持严肃；不苟言笑。
词典not frivolous in talking and joking：不苟言笑。
不苟言笑[bù gǒu yán xiào]
serious in speech and manner; keep one's gravity; not frivolous in talking and joking; reserved; reticent; sedate; sober; taciturn