oblique hint

References in classic literature ?
Are these last throwing out oblique hints touching tophet?
The first oblique hint that Blair might be in active contact with the
Boris preferred an oblique hint leaving John and Tony (literally) to fill in the dots.
My curiosity was piqued by this medley of the visible, the invisible, and the deliberately hidden, a mixture that refuses to disclose more than an oblique hint about histories of which I am ignorant.
An oblique hint was given in London last night that the 700 maintenance engineers and electricians whose strike has now held up national newspaper production for five days might at some future date be prepared to take their wage claim to arbitration.
But it really did seem to be a question about air services to St Helena rather than an oblique hint to Mr Blair that he should sail off into the sunset.