dǔ
block up
Phonosemantic compound. 土 represents the meaning and 者 represents the sound.
Evolution

Bronze script
Late Spring and Autumn (~500 BC)
Seal script
Shuowen (~100 AD)
Clerical script
Western Jin dynasty (266-316 AD)Regular script
ModernDefinitions
dǔ
wall; stop, prevent; stop up; to block up (a road, pipe etc); to stop up (a hole); (fig.) (of a person) choked up with anxiety or stress; wall (literary); (classifier for walls)
Sources