Rashi: It is an expression of Sigim (Tehilim 119:119, i.e. dross). Malbim - also these individuals (refer to 53:3:2:2 and the note there) were like dross silver on earthenware. Their virtue was only external, on their lips. Even Nebuchadnetzar, who showed some honor to Hashem, did not truly seek Him. He was a Rasha, like his colleagues.
2.
Radak (14:3): They veer from the good way. This is like "Nasogu Achor" (Yeshayah 42:17).
2)
What is the meaning of "Ne'elachu"?
1.
Rashi: They were converted to ruin.
2.
Radak (14:3): They became repulsive. This is like "Sir Asher Chel'asah Vah" (Yechezkel 24:6), i.e. filth, just the letters (of the root, Lamed and Ches) are reversed. The same applies to "Af Ki Nis'av v'Ne'elach" (Iyov 15:16).
3)
What is the meaning of "Ein Gam Echad"?
1.
Radak: Not one of [Titus'] soldiers protested against him. Radak (14:3) - also "Gam l'Re'ehu Yisna Rash" (Mishlei 4:20) means 'even'.
2.
Malbim (14:3): Even though the individual who appears to honor Hashem, he does not do good, for his heart is full of sin, and also he denies [Hashem].
