Question

can someone explain in brief what an 'oxymoron' is..??

Answer 1

use of compound and paradoxical words in a writing
in a way that we can infer several meanings of that

Answer 2

It is a combination of words that have a mutually exclusive meaning. An oxymoron is used in poetry and prose as a rhetoric figure. Bit it can also be involunterily and sometimes even enter common language:
Think of the following examples:
bittersweet
loud silence
virtual reality

Answer 3

a phrase contradicts itself.

alone together
jumbo shrimp
plastic glasses

Answer 4

A contradiction. Pianoforte.