奋

Big-person radical on top - a stick figure with outstretched arms and legs, the indexing radical. Traditional 奮 had 大 over 隹 (short-tailed bird) over 田 (field), picturing a bird beating its wings to break free. Modern simplification dropped the bird, leaving big-person above field - still suggesting a person extending themselves with effort.

Bottom 田 'field' - picture of a divided plot of farmland, the grid of paths between paddies. In the original 奮 imagery, 田 was the open landscape over which a bird flexed its wings; modern 奋 keeps the field as the open ground a person strides across with vigour. Compound 奋斗 'to strive' captures its energy.