| 1. | Also called, especially British, adjustable spanner. a wrench having an adjustable jaw permitting it to grasp nuts or the like of different sizes. |
| 2. | something that interferes with functioning; obstacle: He threw a monkey wrench into our plans. |
[muhng-kee-rench] 
| 1. | to ruin (plans, a schedule, etc.) unavoidably or, sometimes, deliberately: The storm monkey-wrenched our plans for a picnic. |
| 2. | to prevent, delay, or sabotage industrialization or development of wilderness areas, esp. through vandalism. |
monkey wrench  (click for larger image in new window) n.
[Origin unknown.] |