Is there any sense in which 'giddy' has not been used?
In most of them, 'avoidance of the word god' is not involved.

A quote in the OED from 1796, "Plain Sense": Lady Almeria was a little giddy-brain.
Rudyard Kipling, 1893, "he put his arm round 'av me, and I came into the sun, the hills an' the rocks skippin' big giddy-go-rounds.
Smollet, 1748, "a parcel of giddy-headed girls."
Fryer, 1698, "The heir .... being of little credit, being a giddy-head."
Armin, 1604, We have many giddie-pated poets ....."