back formation

Formation of a new word by removal of a morph that is or resembles an affix.

Examples: to edit, v. from editor, n.
to lase, v. from laser, n. *

*Note that this last example is especially striking as laser is an acronym of the phrase light amplification by stimulated emission of radiation. The seemingly removed morph er at the end of the noun is thus not the real suffix -er, but a pseudosuffix that resembles the suffix in words like baker, n., lover, n.