suspicious; captious; apt to take umbrage; tetchy ...a1639 obs.
irregularly from umbrace (vb. to surround; to obtain)
FIRST DOCUMENTED USE
a1639 - see EXAMPLE below
"...First, he was to wrastle with a Queens declining, or rather with her very setting Age (as we may term it,) which, besides other respects, is commonly even of it self the more umbratious and apprehensive, as for the most part all Horizons are charged with certain Vapours towards their Evening..."
From: A Parallel Betweene Robert Late Earle of Essex, and George Late Duke of Buckingham
- Henry Wotton