The phrase 'without him noticing' is grammatically correct and is usable in written English.
Example sentence: She quickly slipped the money into his pocket without him noticing.
And tried to bury the body without him noticing.
You couldn't make a false note without him noticing it," said Freidin.
Cameron should be effing and blinding instead at his own party, for it's they who have changed without him noticing.
Later the teams discussed the court case in which a secretary stole £4.3m from a Goldman Sachs banker, much of it without him noticing.
In a clustering miscalculation, however, Ferriss had neglected to seat himself with a view of the restaurant's doorway, so that I entered and was seated without him noticing, and spotted him before he saw me.
He denied to the network's star reporter, Connie Chung, that he had ever struck Holly Maddux, said he had no idea how her body came to spend 18 months in his flat without him noticing it, and thought he had probably been framed by 'one of the large intelligence agencies', because he had stumbled across something he should not have.
A spokesman told Money that it now accepts that it should not have debited the money without giving him notice.
"Defendants have deprived him of that interest without providing him notice and an opportunity to be heard on the question whether he is dangerous".
Quietly, the painter's wife settles back onto the pedestal without him even noticing.
The worst of his attacks, she said, came as retribution for her walking past him without noticing that he was there.
Not yet, maybe, but you can't be around him without noticing an abundance of certain qualities — self-confidence, energy, ambition, and the ability to drive curators bonkers, to name four — that could make him a contender.
