'shadowy past' is a correct and usable phrase in written English.
It is used to refer to a part of someone's life that is unknown or obscure, typically due to someone trying to hide details or simply because key events have been forgotten over time. For example, you could say: "He refused to talk about his shadowy past, and I could only guess at what he had been through."
A father felled by a shadowy past.
Auntie Mei is not alone in her struggle with a shadowy past.
Its director, Tommy Wiseau, is also an enigmatic man with a shadowy past.
This may have to do with the High Bridge's having a shadowy past.
The unique narrative of a voyage tracing the roots of a shadowy past, unclear and confusing, even to those involved.
The awkward outsider and adolescent frees the ghost from the bathroom, forcing the family to confront a shadowy past.
And for the Americans who helped create and nurture the movement, the initial excitement has been tempered by the challenge of managing a huge, and growing, force where many of the men have shadowy pasts.
Guatemala's intelligence services, the most sinister organizations of the war, are supposed to pass to civilian control but are still in the hands of military men with shadowy pasts and still operate without civilian oversight.
All seem to be of the opinion that cycling is a lot cleaner now than it used to be, but are disappointed that so many people managing teams in the sport today have very shadowy pasts: Bjarne Riis and Alexander Vinokourov are two whose names crop up.
This was not an anonymous Jordanian or an Iraqi with a shadowy Baathist past, but someone educated in St John's Wood, Queen's Park and Westminster.
But somehow, in spite of its limitations, this film places Freud exactly where he belongs: in a shadowy, irrecoverable past and right here in our midst, the cause, cure and embodiment of so much that continues to plague us.
