Morphological, from morphology, refers to the formation of words in a given language. Morphology includes derivation, which is the creation of words from separate existing morphemes. One other kind of morphological formation is conversion. Conversion is the formation of new words from existing ones without changing the form (external structure) of the morphology of the originating words.
Conversion is a non-concatenative process that forms new words through modifying the internal structure of morphemes, which is specifically the meaning of morphemes. An example is shovel and shovel: these are shovel the noun and shovel the present tense form of the infinitive verb to shovel. The internal structure of the morphemes of shovel have been altered--meaning has been altered--to generate a new word. The verb "shovel" was converted from the noun "shovel" c. 1440.
Non-concatenative morphological conversion processes contrast with concatenative in that the latter describes formation of new words by putting morphemes together, for example, through derivation utilizing affixes.