From a bio.:
He liked etymology and unusual facts about words. web page Also probably no help:
AGID database There are several ref.'s to it having to do with disease; not the likely meaning here, I think!
Best guess, and it's not a good one, is that he coined the word from parts of others. I first tried a-, but had no credible results for -gid. I suppose -id could refer to that part of our psyches, but the ag- prefix doesn't make a whole lot of sense. In this particular ref., when I looked up ag- I was referred to ad-, which shows these meanings:
ad-
prefix
Definitions:
1. to, toward
adsorb
advance
2. near
adrenal
[< Latin ad "toward, near" < Indo-European] encarta
