| Daft |
| Loco |
| Nuts |
| Loony |
| Goofy |
| Bonkers |
| Touched |
| Tetched |
| Eccentric |
| Pixilated |
| Addlepated |
| A bit daft |
| Half-witted |
| A bit crazy |
| Not all there |
| Feeble-minded |
| A bit eccentric |
| Off one's rocker |
| Non compos mentis |
| Amiably eccentric |
| Crazy in the coconut |
| Slightly off one's rocker. |
| Eccentric, in an amusing way |