In rare cases you might be removing a genuine classical prefix (when an affixed word is in use and the root never has been), but it depends entirely on the word and its etymology. Otherwise, yes, it's just a bit of fun.
I was going to suggest this should be deprefixation, but as reesetee points out, it's a madeupical word anyway. Also, I wondered if the spelling was intentional, to form a portmanteau from deprivation + prefix.
"There is a slight potential problem with this method if the result is a noun." Sionnach is correct... avoid using this method to create nouns from words with a- prefixes. It may get terribly confusing.
I'm rather touched that nobody's yet pointed out my glaring typo... if only one could edit the word after the event.
There is a slight potential problem with this method if the result is a noun. Suppose one wishes to coin the madeupical term "norexic" to describe one's housemate Nora, who never met a snack food she didn't like, and has the embonpoint to prove it. Sentences like "Nora's a norexic" are out.
I believe you allude to this issue in one of your other comments.
But I like this whole new approach to generating madeupical words. So much leaner and more streamlined than those portmanteau coinages.