Both in his sister’s presence, and after she had left the room, the whelp took no pains to hide his contempt for Mr. Bounderby, whenever he could indulge it without the observation of that independent man, by making wry faces, or shutting one eye.
There are no more uses of "indulge" in the book.
Show samples from other sources
She indulges her children more than is good for them.
I indulge my taste for sweets more than is good for me.