"an ardent reader" is a correct and usable phrase in written English.
You can use it any time you want to refer to someone who loves to read or is very devoted to reading. For example: "Rosa is an ardent reader, often devouring multiple books in a single week."
Abramović was an ardent reader in her teens: "Extreme narratives fascinated me.
Lizzie is an ardent reader, a woman of passionate imagination and significant plainness.
(The tsar, Alexander II, was an ardent reader and eventually agreed to free the serfs).
She is also an ardent reader of adventure stories, and possesses both a theatrical imagination and her family's penchant for rewriting the past, that "narrowness of vision which enabled all the Cleves to forget what they didn't want to remember, and to exaggerate or otherwise alter what they couldn't forget".
Caldwell had been an ardent reader and admirer of Boyd's work, especially his book, "Are You Running With Me, Jesus?" Boyd's revelation made Caldwell think about his own views with respect to gay rights.
An ardent reader who regularly consumed two to three books a week, he can no longer make out the print in newspapers or books.
It is chaired by ardent reader, Marie Field, a former highly respected and gifted elementary school teacher who cherishes words and the way they interact and relate to each other.
Does this mean that a novel that is as inaccessible as Finnegans Wake available to a handful of ardent readers is a prime definition of a literary novel?
Byron's poem posed his more ardent readers with a difficult challenge: they not only had to redeem his virtue but restore his sense of pleasure.
When 460 of the more ardent readers of a 142-year-old leftist weekly get together on a cruise ship, things can be a little topsy-turvy.
Wallace's most ardent readers, I felt, utterly failed to make a case that effectively disputed the common, dismissive attitude toward his work that was expressed by many people in the literary circles I knew.
