Usher -- Tameka Raymond Is a Bad Mom

Usher has denied every allegation his ex-wife has made in her motion to wrestle custody away from the singer in the wake of Usher Raymond V's nearly fatal pool accident -- he's even denied she's a good mom.

In the docs -- obtained by TMZ -- Usher is not specific about what he's denying ... he just denies, denies, denies.

Tameka Raymond made various allegations, including that Usher was an absentee parent for 85% of the month, that his aunt failed to properly supervise the boy at the swimming pool, and that he has said he'd prefer that the nanny raise his kids. Usher denied everything.

And there's this ... Tameka claims she's a capable mother. Usher denied that, too.