Full-blown means fully developed, with nothing held back. A full-blown crisis.
It is used of illnesses, arguments and disasters and almost never of anything good. The blown in it means blossomed, from the old sense of a flower fully open.
1adjectivefull-blownFully developed, with nothing held back.
“It went from a disagreement to a full-blown row in about a minute.”
full-blown is a quality.
Full plus blown, the past participle of blow in its old sense of blossoming.
Built from
From full + blown, past participle of blow (“to blossom”).
Etymology from Wiktionary, CC BY-SA