Characteristic - व्याजस्तुतिर्मुखे निन्दा स्तुतिर्या रूढिरन्यथा।
Meaning: Aparent slander or praise becomes ultimately quite otherwise i.e. slander becomes praise and praise, slander.
For example - (1. Illustration of slander/backbiting by a slanderer) कः स्वधूनि विवेकस्ते पापिनो नयसे दिवम् ।
(Meaning: Oh Pious river Ganga. where is your culture, your modesty in taking sinners to heaven ?)
Here apparently criticism levelled against Ganga is that she has not remained modest / cultured, but in fact implicily Ganga is praised (as Ganga is the deity who takes even sinners to heave), So here the figure of speech is 'Vyajastuti i.e. irony.
(2. backbiting by a person who praises, eulogises)
किमंह वदामि खल दिव्यमते गुणपक्षपातभितो भवतः ।
गुणशालिनो निखिलसाधुजनान् यदहर्निश न खलु विस्मरसि ॥
(Meaning: Oh! wicked person with brilliant, divine intelligence! What can I say about your partiality for virtues/merit/ quality? You really do not forget all the virthous/meritorious persons any time ?)
Here it appears that a wicked person does not forget virtuous persons any time. But the meaning, the intent is that a wicked person troubles good persons all the time. So, here the figure of speech is 'Vyajstuti i.e. irony.