What is the meaning of "va'Teyabev"?
Rashi #1: It is an expression of speech, like "Niv Sefasayim" (Yeshayah 57:19).
Rashi #2: It is an expression of moaning, like the Targum of Teru'ah 'Yebava' (Vayikra 23:24).
Rashi #3, Radak citing Targum Yonasan: It is an expression of seeing - "b'Vavas Eino" (Zecharyah 2:12).
What is "ha'Eshnav"?
Rashi: It is a window.
Malbim: It is a window via Chachmah, She used magic to infer what happened to him. She saw him dead, and moaned.
What is the difference between Boshesh and Echeru?
What are Pa'amei Markevosav?
Malbim: They are runners to inform what happened to [his army]. Targum Yonasan - they bring a letter about the victory.