gammer /gamˈər/ (archaic or dialect; derogatory)

An old woman (masc gaffer)

• onychophagists
• onychophagy
• Onychophora
• onychophoran
• onychophorans
• onymous
• on your bike
• on your mark
• on your marks
• onyx
• onyxes
• onyx marble
• onyx marbles
• o/o
• oo
• oo'
• oo-
• oobit
• oobits
• oocyst
• oocysts
• oocyte
• oocytes
• oodles
• oodlins