keystones is a form of:

Blackguard



noun
1.
មនុស្សពាល, មនុស្សចោលម្សៀតឥតបានការ, មនុស្សថោកទាប, អពមង្គលជនទុច្ចរិត
verbpast tense: blackguarded ; past participle: blackguarded ; present participle: blackguarding ;
1.
(TRANSITIVE) ជេរប្រទេច
ENGLISH MEANING
noun
1.
A person of stained or low character, esp. one who uses scurrilous language, or treats others with foul abuse; a scoundrel; a rough.
2.
The scullions and lower menials of a court, or of a nobleman's household, who, in a removal from one residence to another, had charge of the kitchen utensils, and being smutted by them, were jocularly called the "black guard"; also, the servants and hangers-on of an army.
3.
The criminals and vagrants or vagabonds of a town or community, collectively.
4.
A vagrant; a bootblack; a gamin.
adjective
1.
Scurrilous; abusive; low; worthless; vicious; as, blackguard language.
verbpast tense: blackguarded ; past participle: blackguarded ; present participle: blackguarding ;
1.
(TRANSITIVE) To revile or abuse in scurrilous language.