The phrase "a certain older" is not correct in standard written English.
It may be intended to refer to a specific older person or thing, but it lacks clarity and proper structure.
Example: "I met a certain older gentleman at the event who shared fascinating stories."
Alternatives: "a particular older" or "a specific older".
For instance, a certain young actress--let us call her Laurie Masters--has for many years been represented by a certain older and tougher I.C.M. agent--let us call her Bonnie Klein.
"Maybe if the median age was 45 to 50, a film like 'Shame' might show up, which I thought was a brilliantly rendered piece but a subject matter that you don't expect a certain older demographic would flock to see," she said.
It's not exactly romantic, but there is a certain old-world charm to it.
He was of a certain old-fashioned type — lanky, large-nosed, with an out-sized Adam's apple.
The necessary intimacy -- it's a three-person play, including an actor-pianist -- remained, joined to a certain old-time Broadway glamour that felt right.
In a house where cinematic realism rules, David Hockney's spare sets and his use of stylized painted flats has a certain old-fashioned charm.
Templeton, the Guest estate, is dedicated to a certain old-money-by-way-of-England world that has always been captivating to the less well born.
The two also have an understanding about when a certain old man can put on a hat of bells and walk around his father's Christmas fantasy: any time he wants.
Cesar plus military types (who always add a certain old-school glamour to a major trophy presentation, in my book, but that's a discussion for another day) The cavaliers had seen off the roundheads.
She stood before a tatty display tracing the source of Gabrovian wit to a certain Old Minyo, a 19th-century local of fabled abstemiousness who was said to have carried his shoes on long walks, so as to spare their soles, and who sat in the dark to save candle wax.
In this film, he produces a novel, raffish charm as the silver-tongued rogue, and a certain old-fashioned masculine mass and substance, which he wears lightly, but in such a way as to signal unmistakablyhis arrival in the big-screen big league.
