-eroo
a suffix that creates familiar, usually jocular variations of semantically more neutral nouns; normally added to monosyllabic bases, or merged with bases ending in -er: flopperoo; smackeroo; switcheroo.
Origin of -eroo
of unclear orig.; perhaps extracted from
buckaroo, though this word appears to have been conformed to a preexisting suffix (or word), the stress and final tense vowel being otherwise unaccounted for