How are Yisrael a "Mashal"?
Radak: Any bad or disgraceful matter, they make it a metaphor for Jews.
Malbim: We were not like a disgraced matter that no one talks about. We were a parable among the nations, for we were honored and Am Hashem in olden days, and we descended wondrously.
What is "Menod Rosh"?
Radak: They move their head [condescendingly] over us, like "Yaftiru v'Safah Yani'u Rosh" (22:8).
Is there a difference between "Goyim" and "Le'umim"?
Malbim: Yes. Goyim are collections [of people]; Le'umim are nations with a common creed. The latter shook their heads over us due to creed - they mocked our Torah and belief.
What is the grammatical form of "ba'Le'umim"?
Radak: The Lamed is part of the root, like "u'Le'om mi'Le'om Ye'ematz" (Bereishis 25:23).