calumniate

As Verb : to utter maliciously false statements, charges, or imputations about someone.

Synonyms : malign, slander

Related Words : libel, denigrate

Usage : Humans are basically sadistic; watch how toddlers calumniate their siblings, just to watch the spectacle of the punishment

Connotation : negative

platitude

Root : plat, meaning flat

As Noun : a trite remark, commonplace statement. Also, dull, insipid

Synonyms : prosaism, cliche
Antonyms : esoteric (suggest by 'sat', thanks :) )

Related Words : commonplace, banality

Usage : The platitudes of the orator would have had impressed the majority of the junta, but they failed to attract the attention of critics.

Connotation : critical of speech

venal

Root : venum, meaning sale; vasna, meaning price

As Adjective : capable of being bribed, capable of being corrupted.

Synonyms : bribable, corruptible, dishonest, purchasable
Antonyms : incorruptible

Related Words : dishonest, unethical, unprincipled

Usage : A few venal bureaucrats in the administration are responsible for the whole system being damned.

Connotation : negative

effeminate

Root : femina, meaning woman.

As Noun : having feminine qualities untypical of a man : not manly in appearance or manner

As Verb : marked by an unbecoming delicacy or overrefinement.

Synonyms : feminine, girlish, sissy, unmanly, womanish, womanlike, womanly
Antonyms : manlike, manly, mannish, masculine

Related Words : old-maidish, overnice, spinsterish; dandyish, foppish, sappy

Usage : Effeminate guys are often bullied and abused in schools (noun)
Usage : (someone please suggest verb usage)

Connotation : Often negatively used, to described homosexuality. Also used to describe feminine behaviour as a result of a medical condition.