What does Tybalt mean when he says, "I'll not endure him"?

In
act 1, scene 5,has spottedMontague at the Capulet feast, and he cannot believe that the sworn
enemy of his family would dare to make an appearance.himself reaches out to Tybalt, telling him,
"And, to say truth, Verona brags of him / To be a virtuous and well-governed youth"
(72€“73). Further, Lord Capulet tells Tybalt that his acting so unwelcoming and angry is not
festive. That is when Tybalt delivers these lines:

It fits
when such a villain is a guest.
Ill not endure him. (I.v.80€“81)

Tybalt is saying, in modern English, "I won't stand for
this." He sees Romeo as an intruder and an enemy and refuses to stand idly by and allow his
enemy to enjoy a great party at his uncle's expense. This fits with Tybalt's persistently
quarrelsome personality, which is ultimately his demise.

Lord Capulet
effectively puts Tybalt in his place in the next lines, reminding him that he (Lord Capulet) is
the master of this house and makes the rules there.