Unsusceptible

Imagination, a licentious and vagrant faculty, unsusceptible of limitations, and impatient of restraint, has always endeavored to baffle the logician, to perplex the confines of distinction, and burst the enclosures of regularity.

Source: wiktionary

Mortals, rejoice! the very Angels quit Their mansions unsusceptible of change, Amid your pleasant bowers to sit, And through your sweet vicissitudes to range!

Source: wiktionary

It would be mortifying to the feelings of many ladies, could they be made to understand how little the heart of man is affected by what is costly or new in their attire; how little it is biased by the texture of their muslin, and how unsusceptible of peculiar tenderness towards the spotted, the sprigged, the mull, or the jackonet.

Source: wiktionary

I was in a dull state of nerves, such as everybody is occasionally liable to; unsusceptible to enjoyment or pleasurable excitement; one of those moods when what is pleasure at other times, becomes insipid or indifferent; the state, I should think, in which converts to Methodism usually are, when smitten by their first “conviction of sin.”

Source: wiktionary