He has a habit of putting his foot in his mouth at important meetings, which often embarrasses his colleagues.

putting 是动词 put 的现在分词形式，put 的基本意思是"放置"。 his 是形容词性物主代词，表示"他的"。 foot 的意思是"脚"。 in 是介词，表示"在...里面"。 his 再次出现，仍然是形容词性物主代词"他的"。 mouth 的意思是"嘴"。 put one's foot in one's mouth 是一个英语习语，字面意思是"把脚放进嘴里"，实际含义是"说错话、失言"，通常指无意中说了冒犯或尴尬的话。