| 1 | English | fool | A person with poor judgment or little... |
| 2 | French | fouler | to stamp, impress, dent; to mill; to walk on,... |
| 3 | Middle French | fouller | to mistreat |
| 4 | Old French | foler | to destroy; to mistreat |
| 5 | Medieval Latin | fullo | fuller |
| 6 | Latin | fullo | fuller |
| 7 | Proto-Indo-European | bʰleh₃- | bloom, flower |
| 8 | Proto-Indo-European | bʰel- | to sound; to speak, roar, bark; shiny, white; to... |
| 9 | Proto-Indo-European | bʰōl- | — |