- oaken10
- oakum13
- oared6
- oases5
- oasis5
- oasts5
- oaten6
- oater5
- oaths7
- oaves9
- obeah10
- obeli9
- obese8
- obeys10
- obias8
- obits8
- objet17
- oboes8
- obole9
- oboli9
- obols9
- occur12
- ocean9
- ocher10
- ochre10
- ochry12
- ocker12
- ocrea8
- octad9
- octal9
- octan9
- octet8
- octyl11
- oculi10
- odder7
- oddly10
- odeon7
- odeum10
- odist6
- odium10
- odors6
- odour7
- odyle9
- odyls9
- ofays10
- offal12
- offed12
- offer11
- often9
- ofter8
- ogams10
- ogees7
- ogham12
- ogive11
- ogled9
- ogler8
- ogles8
- ogres7
- ohias7
- ohing10
- ohmic13
- oidia6
- oiled7
- oiler6
- oinks10
- okapi12
- okays11
- okehs11
- okras9
- olden8
- older7
- oldie7
- oleic9
- olein7
- oleos6
- oleum10
- olios6
- olive10
- ollas7
- ology10
- omasa8
- omber11
- ombre11
- omega10
- omens9
- omers8
- omits8
- onces9
- onery8
- onion7
- onium10
- onset6
- ontic9
- oohed8
- oomph13
- oorie5
- ootid6
- oozed15
- oozes14
- opahs10