Mr. Clennam is visiting the debtors prison:
" As they eyed the stranger in
passing, they eyed him with borrowing eyes--hungry, sharp,
speculative as to his softness if they were accredited to him, and
the likelihood of his standing something handsome. Mendicity on
commission stooped in their high shoulders, shambled in their
unsteady legs, buttoned and pinned and darned and dragged their
clothes, frayed their button-holes, leaked out of their figures in
dirty little ends of tape, and issued from their mouths in
alcoholic breathings.

The practise of begging. If it were not for the context, and the similarity to "mendicant" I would have supected it
of being a typo for "mendacity".

These two are good to put on our easily confused lists, although we do hear of mendacious mendicants. Most recently, two friends of mine told the story of traveling the interstate highway where at a rest station a couple with a baby was 'working' the crowd to get money for a broken-down car. The tale was that they just needed enough money for gas, but my friends observed them receive money over and over as they went to different spots at the rest station. They even had a baby in arms to get more sympathy for their tale of plight.

Hey! They're related along with 'amend'! Look at this from
MW:
Etymology: Middle English, from Old French amender, modification of Latin emendare, from e, ex out + menda fault; akin to Latin mendax lying, mendicus beggar, and perhaps to Sanskrit mindA physical defect