Cois"tril (?), n. [Prob. from OF. coustillier groom or lad. Cf. Custrel.]
1.
An inferior groom or lad employed by an esquire to carry the knight's arms and other necessaries.
[Written also
coistrel.]
2.
A mean, paltry fellow; a coward.
[Obs.]
Shak.
© Webster 1913.