hiepogymnia: how do you write the first syllable?
heard as hiepogymnia
spelled hypogymnia
As hy. Hypogymnia.
What the ear did
The syllable is said like the word high, and ie is one honest English way to write that. The prefix is the Greek hypo, the one in hypodermic and hypothermia, and it always begins hy.
H-Y-P-O-G-Y-M-N-I-A
The full entry for hypogymnia covers the name itself.