Merciless is a related term of barbarous.
As adjectives the difference between merciless and barbarous
is that merciless
is showing no mercy; cruel and pitiless while barbarous
is not classical or pure.
showing no mercy; cruel and pitiless
* (obsolete) barbarouse
Not classical or pure.
Like a barbarian, especially in sound; noisy, dissonant.
- I did but prompt the age to quit their cloggs
- By the known rules of antient libertie,
- When strait a barbarous noise environs me
- Of Owles and Cuckoes, Asses, Apes and Doggs - (1673)