What is the difference between pleonasms and tautologies, and are they considered bad practice, to be avoided at all cost? Or not? And how about oxymorons?
Tautology is the expression of an idea by means of 2 different words. This is generally regarded as bad pratice. As far as pleonasms are concerned, the point is slightly different : we enter the realm of rhetorics and stylistics. Pleonasms have been used by great poets and writers just as oxymorons.
O brawling love, o loving hate,
O anything of nothing first create.
The co-presence of two seemingly contrary "signifiers" is close to a mere contradiction and yet it gives off a mighty effect.
You should be cautious with those stylistic means and avoid them within your academic or school writings .