| Part of speech | unknown part of speech |
|---|
| Danish | gruble |
|---|---|
| Dutch | zich het hoofd breken; zijn hersens afpijnigen |
| English | puzzle over; rack one’s brains; rack one’s brain |
| Faeroese | brýggja høvur; grunda; hugsa djúpt |
| German | grübeln; angestrengt nachdenken |
| Icelandic | velta fyrir sér |
| Norwegian | gruble |
| Portuguese | esforçar‐se mentalmente |
| Saterland Frisian | gruubelje; simulierje |
| Spanish | cavilar; devanarse los sesos |
| Swedish | grubbla |