". But it had an influence in placing obstacles in the way of her
association with Mrs Gowan by making the Prunes and Prism school
excessively polite to her, but not very intimate with her; and
Little Dorrit, as an enforced sizar of that college, was obliged to
submit herself humbly to its ordinances.

a sizar (a student who received money for college expenses in exchange for being a servant to other students).