The phrase "was careless enough" is grammatically correct and can be used in written English.
It is typically used to describe someone's level of carelessness or lack of caution in a situation. Example: "John was careless enough to leave his phone on the table while he went to the bathroom, and when he came back, it was gone."
"Kabila was careless enough to ignore the concerns of the people who created him," said one African diplomat.
After Hampton was careless enough to potentially injure his forearm, he flung his cap ahead of him and bolted to the clubhouse.
She announced her decision in a radio interview — seemingly on a whim — and referred to the party of Vladimir Putin as "that fucking party" and "that shit into which I was careless enough to step".
She announced her decision in a radio interview—seemingly on a whim and referred to the party of Vladimir Putin as "that fucking party" and "that shit into which I was careless enough to step".
By 1967 we must have known that jet aircraft were bringing these patterns of industry and travel to an end; even so, I was careless enough to be in a Glasgow dentist's chair having a tooth pulled – personal decay at odds with a great historic moment – when the Clydebank hull at last slid into the river as the QE2.
In our opinion, an unwanted bot that would start behaving that way would not go unnoticed by a network administrator that did not accept such practice, and it would not remain limited to a few machines if the network administrator was careless enough not to bother about it.
Some like to drink it, others need it to draw out venom, having been careless enough to be stung by lurking weaver fish.
If you've been careless enough to already have children then for God's sake never mention them.
They glean whatever they can about your political views, if you are careless enough to express them in public, and your personal foibles.
It seems unlikely that a decorated army veteran, parachutist and instructor would be careless enough with a pistol to accidentally shoot himself in the head.
Fellow swimmers objected, partly because they found the soldiers unappealing aesthetically - they had been careless enough to lose various limbs - but also because they 'hadn't paid'.
