WordWeb Online

1. Inclined to shake as from weakness or defect
   "a rickety table"
   - shaky, wobbly, wonky
    
2. Affected with, suffering from, or characteristic of rickets
   "rickety limbs and joints"
   - rachitic
    
3. Lacking bodily or muscular strength or vitality
   - decrepit, debile, feeble, infirm, sapless, weak, weakly

Derived forms: ricketiest, ricketier

See also: frail, ill, ricketiness, sick, unstable