scurrilous

Concise Oxford English Dictionary © 2008 Oxford University Press:
scurrilous /ˈskʌrɪləs/

▶adjective making scandalous claims about someone with the intention of damaging their reputation.

■ humorously insulting.

– derivatives
scurrility noun (pl. scurrilities),
scurrilously adverb,
scurrilousness noun.

– origin C16: from Fr. scurrile or L. scurrilus (from scurra ‘buffoon’) + -ous.