무꾸

Etymology
Likely from, unattested dialectal form of Seoul , connective allomorph of , with the epenthetical vowel of a suffix−probably topic marker  or accusative marker −reanalyzed as part of the root. The new vowel was then assimilated with the first vowel, perhaps under influence from Seoul prestige dialect. The development would have been like this, if the topic marker is assumed to have been the suffix:
 * 뭇근 > *뭇근/*뭇그는 > *뭇군/뭇구는 > modern 무꾼/무꾸는

Compare, where the fused suffix was apparently the nominative.