All 3 Uses

allude
in
Never Let Me Go
(Auto-generated)

If she decided someone should be expelled, for example, and she sensed opposition, she'd just allude darkly to stuff she knew "from before."†
p. 52.6

allude = to make an indirect reference
But now it was okay, almost required, every now and then, to make some jokey allusion to these things that lay in front of us.†
p. 84.9 *

allusion = an indirect reference
Just every now and then, Ruth would allude to it.†
p. 235.5

allude = to make an indirect reference

Definitions:

(1) (allude)
to make an indirect reference

The expression, no allusion can mean "not even an indirect reference"; i.e., neither a direct nor an indirect reference to something.
(2) (meaning too rare to warrant focus)