The phrase "act on a contrary" is not correct in standard written English.
It seems to be an attempt to express acting in opposition to something, but it is not a commonly used expression.
Example: "Despite the evidence presented, he chose to act on a contrary view, believing his instincts were more reliable."
Alternatives: "act in opposition" or "take a contrary action".
She acted in a contrary manner to her mother.
In a higher order thinking setting, one may act on the contrary to others or even may not act logically in order to save the situations to their utmost.
On a contrary, suppose that but.
For example, consider an agent who succumbs to contrary inclination of exactly the type expected when the time comes to act on a truly stupid resolution.
The controversy has ensnared another M5S politician, Luigi Di Maio, who was alerted about the Muraro investigation by Raggi but never acted on it, contrary to the spirit of internal M5S rules.
For the strict mode, fewer but more accurate contigs are generated, while nonstrict mode acts on the contrary.
"Kanye …" By this point the Chainsmokers are the second most streamed act on the planet and, contrary to prophecy, Spotify statistics show that not one of their 10 most popular songs is, in fact, Selfie.
In other words, most people are unlikely to suggest and act on ideas that are contrary to the status quo - i.e. ideas that are innovative - because of their fears of rejection or not fitting in and, in the case of the business world, their fear of being fired.
However, we must ensure that our return, now officially endorsed, does not result in a trivialization of our foreign policy or a deterioration of our ability to make decisions and act, but on the contrary, in the growth of our influence and capabilities.
To discriminate against a married couple requires a secular interest which was lacking in the Defense of Marriage Act -- on the contrary, the legislative record showed evidence of bias.
