"capricious about" is a correct and usable phrase in written English.
It means to be unpredictable or impulsive when making decisions or choices. Example: The new boss was known for being capricious about his management style, often changing his mind and making last-minute decisions that left his employees feeling confused.
History is capricious about what it preserves and what it consigns to its dustbin.
There is nothing capricious about the title of Malcolm McLaren's new album, "Paris".
"Capricious Maneuvers" is a tightly constructed garment — nothing capricious about it — and yet it breathes freely.
AC/DC has been shrewd, if at times capricious, about the way it licenses its music.
The fear was exacerbated by the fact that the new law made it possible for landlords to be utterly capricious about the increases.
The novelist Richard Price, who also wrote for "The Wire," told me there's nothing capricious about such thorough revision: "You really need a single sensibility at the top, a writer-producer who's a ruthless rewriter.
From this you may infer that parents make arbitrary and capricious decisions about how much spending money is sufficient, or that an annual survey about pocket money is not an entirely reliable reflection of reality, or both.
Even before the airport suicide attack, Mr. Medvedev's visit to Davos — as well as his modernization policy over all — had been dogged by concerns about Russia's capricious legal system, and about whether it was scaring away foreigners.
They were jealous, capricious, closely informed about our daily lives.
A fourth warned about capricious currents at Hell Gate that once nearly overwhelmed his ocean-going sailboat.
Frank, a charming if capricious Irishman, talks about his life as a conman, "balanced somewhere between the absurd and the momentous".
