Here are some links for lyrics & more information:
Shoshanat Yaakov with Chabad (includes an audio track)
Know the Words!: Shoshanas Yaakov (with inspiration regarding Charvona)
While we love singing “Baruch Mordechai Hayehudi!--Blessed is Mordechai the Jew!”, there is another stanza which reads: “Arur Zeresh eishet mafchidi—Cursed is Zeresh, the wife of my terrorist.” (That is how the book of Rav Levi Yitzchak Bender’s lectures, Words of Faith, translates mafchid: terrorist.)
The word mafchid is literally “a frightener” (as in “one who frightens”) or “scary one” (as in “one who scares”). So mafchidi is like my own personal frightener, one who scares & terrorizes me — my own personal “terrorist.”
In the name of the Arizal (Netiv Yitzchak 128), Rav Bender explains that there is a klippah (a spiritual "shell" of spiritual blockage) called “Zeresh” that injects fear into the heart of a person...and even makes him paranoid.
And this stanza in Shoshanat Yaakov remedies fear, as Rav Bender explains:
“About this we say, ‘Cursed is Zeresh, Arur Zeresh’ — to subjugate that klippah which terrorizes a person.”
(Words of Faith, Vol. I, page 364)
But all that anxiety and fear are really the klippah called Zeresh, the evil conniving wife of Haman.
B’ezrat Hashem, if we say "Arur Zeresh! — Cursed is Zeresh!" with enough heartfelt gusto, we can nullify & overcome that awful klippah.
(Don’t give in to terror!)