@@ -20,1 +20,1 @@
-<gloss>under-shoulder swing-down.</gloss>
+<gloss>under-shoulder swing-down</gloss>

Daijr, Koj, GG5, etc.

Probably better to lead with the usual short name of the sumo move, then follow with the more detailed one. The refs seem to have 肩透かしを食わせる as the real "dodge".
(Richard lectures in Japanese at my alma mater....)

@@ -20,1 +20,2 @@
-<gloss>technique of grasping the arm of the opponent, the moment he comes forward, while stepping out of line and pushing down on the shoulder blade with the other hand, thus pulling him down</gloss>
+<gloss>under-shoulder swing-down.</gloss>
+<gloss g_type="expl">technique of grasping the arm of the opponent, the moment he comes forward, while stepping out of line and pushing down on the shoulder blade with the other hand, thus pulling him down</gloss>
@@ -24,0 +25,1 @@
+<xref type="see" seq="2102880">肩透かしを食わせる・かたすかしをくわせる</xref>
@@ -29,2 +31,2 @@
-<gloss>a disappointment</gloss>
-<gloss>a letdown</gloss>
+<gloss>disappointment</gloss>
+<gloss>letdown</gloss>

A Japanese thesaurus gives the following synonyms (amongst others) for 肩すかし: 
拍子抜け; 期待はずれ ・ 「ガックリ」 
http://thesaurus.weblio.jp/content/肩透かし

広辞苑 definition of 肩透かし (sumo sense):
相撲の手の一つ。相手が出てくるところを、差してで相手の腋の下を抱え込むようにして体を開くと同時に、他方の手を相手の肩にかけ、手前
に引き倒すこと。

決まり手 video demonstation：
http://www.youtube.com/watch?v=DYRJqa87-nw
(position 1:15 - 1:40)

Typically, other dictionaries give the sumo sense first, presumably because the figurative sense(s) which 
follow are derived from it.

EDICT's sumo definition is so brief that one can barely discern the connection between the sumo sense and the 
figurative senses (or even understand it at all). Typically, in dictionaries, there is a more descriptive 
definition such as 

相撲の手の一つ。相手が出てくるところを、差してで相手の腋の下を抱え込むようにして体を開くと同時に、他方の手を相手の肩にかけ、手前に引き倒すこと。
[from 広辞苑]

My suggestion is: "technique of grasping the arm of the opponent, the moment he comes forward, while stepping 
out of line and pushing down on the shoulder blade with the other hand, thus pulling him down"

You can see it clearly at the following 決まり手 video demonstation：
http://www.youtube.com/watch?v=DYRJqa87-nw
(position 1:15 - 1:40)

The "dodging; parrying" sense comes from observing what the victor does in a 肩すかし (i.e. "stepping out of 
line", in my proposed definition).

Another, perhaps more common sense, which seems to be largely missing from dictionaries, is "a 
disappointment; a letdown". It comes from observing what happens to the loser. He makes an attacking 
movement, only to find himself on the ground a moment later. Here are some examples of the usage of 肩すかし in 
that sense:

肩すかし・・・. ものすごく期待してましたが、...

昨夜は真っ白に見えていたのに気がつかないうちに雪は雨に変っていたんでしょう。「いざ雪かき」と意気込んでいたのにちょっと拍子抜けというか肩すかし・・・

行ってきましたが、正直言って肩すかしをくらった感じでした。

これは意外にあっさり、さっぱり、辛くない。ハーブの香りはバッチリしてるんだけど、けっこう「ガッツーン」というインパクトを期待していたせいか、肩すかし。

あまりに普通なデザインに肩すかしを喰った。もう少しあそび心を感じるものだと思っていたから・・・・.

何度か肩すかしをくらったが、ようやく実食ことができました。

デザートは、フルーツサバイヨン ---- これも無難な感じ...あまりに、ビジネスの食事への期待感が大きすぎたせいか、肩すかし感は否めません！

@@ -19,0 +19,5 @@
+<field>&sumo;</field>
+<gloss>technique of grasping the arm of the opponent, the moment he comes forward, while stepping out of line and pushing down on the shoulder blade with the other hand, thus pulling him down</gloss>
+</sense>
+<sense>
+<pos>&n;</pos>
@@ -24,2 +29,2 @@
-<field>&sumo;</field>
-<gloss>under-shoulder swing down</gloss>
+<gloss>a disappointment</gloss>
+<gloss>a letdown</gloss>

@@ -24,1 +24,2 @@
-<gloss>under-shoulder swing down (sumo)</gloss>
+<field>&sumo;</field>
+<gloss>under-shoulder swing down</gloss>