"The last face was so horrible and so simian that he gazed at it in amazement...."See in text(I.)
The adjective “simian” means “monkey-like.” Mr. White's vision of a monkey’s face in the flames doesn’t bode well for him. It suggests that the paw’s power to grant wishes is real and that perhaps they should have listened to Morris’s warnings. However, there is also a rational explanation for Mr. White’s visions: he’s up late and has been drinking, so he’s susceptible to seeing horrible things in the fire.
"He darted round the table, pursued by the maligned Mrs. White armed with an antimacassar...."See in text(I.)
W. W. Jacobs does not entirely abandon his humorist roots; this moment of slapstick comedy where Mrs. White chases her son around the house with an “antimacassar”—a noun which means a “clothing covering to prevent staining on the back of a chair”—is a stark contrast to the darkness in the rest of the story.
The noun “fakir” refers to a person of Muslim (or sometimes Hindu) religion who lives off of the charity of others. Often, fakirs were thought to be magical or in possession of objects with supernatural powers. This is partly because of the Englishes’ tendency at the time to view those of other heritages as otherworldly.
The adjective “rubicund” suggests that Morris’s “visage”—another word for “face”—is reddish or ruddy, likely from habitually drinking alcohol. Morris drinks quite a bit during his visit, and the Whites seem to keep up with him.
The word "offhandedly" means casually. The sergeant-major speaks offhandedly about magic because he has probably seen a lot of it during his twenty-one years in India.
The verb "to condole" means to express sympathy. In this context, Mr. White and his visitor are likely discussing the visitor's difficulties in making his way to the house.
"resignation--the hopeless resignation..."See in text(III.)
The repetition of "resignation," especially paired with "hopeless" in the second repetition, conveys the opposite of what the word "resignation" really means. Here, it's as if repeating the word might make accepting what happened easier, but at the same time pairing the word with "hopeless" expresses just how difficult and seemingly impossible the task truly is.