What is "Tiflatztecha" that enticed Edom?
Rashi: It is your frenzy. You were quick and frenzied to arouse your hatred for your brother. Some say that it is an expression of Palatzos (shock), and some say that it is an expression of Mifletzes (monstrosity).
Radak #1: This is idolatry (Malbim - an image), like "Asher Asesah Mifletzes la'Asherah" (Melachim I, 15:13).
Radak #2: The fear 1 of you that was on your neighbors due to your success.
Radak citing Targum Yonasan: Your foolishness.
Radak: This is like "Palatzos Bi'asasni" (Yeshayah 21:4).
What was Edom enticed to do?
Rashi: To harm [Yisrael].
Radak: (a) To speak harshly. (b) To harm even 1 your brother Yakov.
Malbim: To consider itself to be at the highest level.
In all editions I found, Radak says here 'Lehagdil Peh u'Lehara Af', and in Ovadyah 1:3, 'Lehagdil Peh u'Leharchiv Af (increase anger).' Perhaps also here, the text said u'Leharchiv, and a scribe 'fixed' it to be Lehara, like Rashi. (PF)
What is "Zedon Libecha"?
Targum Yonasan: The evil of your heart.
Malbim: It is intentionally denying principles of Emunah.
What does the verse teach about "Zedon Libecha"?
Radak, Malbim: [Together with Tiflatztecha] it enticed you.
What are "Shochni" and "Tofsi"?
Rashi: They are Shochen and Tofes; the Yud is extra. Radak - the same applies to "Chotzvi Marom Kivro" (Yeshayah 22:16) and similar verses.
What are "Chagvei ha'Sela"?
Rashi (Ovadyah 1:3): [Places of] fear 1 . This is like "v'Haysah Admas Yehudah l'Mitzrayim l'Chaga" (Yeshayah 19:17). The Vov is extra, like the Vov in "Katzvei" (Tehilim 65:6) and "ki'Mtachavei" (Bereishis 21:16). The root [of ki'Mtachavei] is only the letters Tes and Ches.
Rashi (Shir ha'Shirim 2:14): They are clefts or breaks in the rocks. This is like "Yachogu v'Yanu'u ka'Shikor" (Tehilim 107:27), "v'Haysah Admas Yehudah l'Mitzrayim l'Chaga" (Yeshayah 19:17).
Radak: Chagvei is like "Chug ha'Aretz" (Yeshayah 40:22, the ball of the earth), i.e. around the rock. This refers to the top of the rock on which the tower is built. This refers to Har Se'ir.
Radak citing Targum Yonasan: Mountain peaks.
What is the significance of dwelling "b'Chagvei ha'Sela"?
Radak (Ovadyah 1:3): When you dwelled in Har Se'ir, you thought that you are protected in it, and no one will make you descend from it.
Malbim: The place is fortified, due to (a) The strength of the place (a hole in a rock); (b) Its elevation. (You think that due to these, no one can defeat you.)
What is a "Nesher"?
Refer to Vayikra 11:13:151:1 and the note there.
What is the meaning of "Sagbi'ah ka'Nesher"?
Radak: You will elevate the place of your dwelling like a Nesher, which flies higher than all [other] birds. Malbim - this will be for the sake of casting you down in the days of Mashi'ach. If I would cast you down from a low place, the fall would not be so great!