"coup d'etat" suggests success.  AFAIK, this term does not.  all J-E sources have 'riot'

@@ -20,1 +20,1 @@
-<gloss>coup d'état</gloss>
+<gloss>riot</gloss>

GG5 daijr koj ja:WP
http://ja.wikipedia.org/wiki/一揆

ja:WP has a long discussion of shades of meaning and English translation (as “riot, revolt”), which may be worth reading carefully (I took a look at it but not esp. carefully).

* Elaborate – esp. Japanese historical, a *revolt*
(Dicts note “Japanese”, though not exclusively Japanese – also used to translate German “Putsch”, as in ミュンヘン一揆)
* Not “riot” except in very broad sense of the word, hence remove as misleading
* Also, remove articles (“a, an”)
(Local bar is called 一揆, hence interest in term.)

@@ -16,2 +16,5 @@
-<gloss>(a) riot</gloss>
-<gloss>an insurrection</gloss>
+<gloss>uprising (esp. in Japan since middle ages, e.g. peasant uprising)</gloss>
+<gloss>revolt</gloss>
+<gloss>insurrection</gloss>
+<gloss>putsch</gloss>
+<gloss>coup d'état</gloss>