"raw silk" was correct. Apologies.
1. untreated silk fibres reeled from the cocoon. 2. fabric woven from such fibres.

@@ -22 +22 @@
-<gloss g_type="expl">traditional rough-surfaced cloth woven from silk</gloss>
+<gloss g_type="expl">traditional rough-surfaced cloth woven from raw silk</gloss>

sankoku:
紬：つむぎ　真綿（まわた）などからとった、上等な絹糸。また、それで縫った、あらい手ざわりの縫物


https://www.weblio.jp/content/つむぎ
daijs: 紬 only
Secondary source lists 紡ぎ only as a verb form for 紡ぐ, not as a synonym for 紬
日本語活用形辞書 索引トップ用語の索引ランキング
紡ぎ
読み方：つむぎ
ガ行五段活用の動詞「紡ぐ」の連用形、あるいは連用形が名詞化したもの。

https://en.wikipedia.org/wiki/Tsumugi_(cloth)
 Because of this structure, tsumugi is rough-surfaced, soft and drapey, softening further with age.

Originally, tsumugi was homemade from domestic or wild-gathered silkworm cocoons that had been broken by hatching[8] or were irregularly formed.[4] Unlike the long-fiber silk, such cloth was permitted to peasants.[9] Traditionally a peasant cloth, handmade tsumugi is very labour-intensive to produce, and has become expensive over time, valued as a luxury folk-craft.

紬, 紡ぎ does not appear except once as a verb, 糸を紡ぎだしたものが紬糸である
https://ja.wikipedia.org/wiki/紬

紡績#手紡ぎ All about spinning, not about the fabric
https://ja.wikipedia.org/wiki/紡績#手紡ぎ

https://en.wikipedia.org/wiki/Tsumugi_(cloth)　紬
https://en.wikipedia.org/wiki/Kumejima-tsumugi　久米島紬
https://en.wikipedia.org/wiki/Yūki-tsumugi　Yūki-tsumugi (結城紬) is a variety of silk cloth produced in Japan, 

The English wikipedia page to pongee has no xref to Japanese
https://en.wikipedia.org/wiki/Pongee

紬	324380	53.6%
紡ぎ	280672	46.4%

The usual gloss in English for "紬" now appears to be the romanized tsumigi.  It is considered to be "a japanese pongee".  (You can search Ebay, or google for tsumigi). 

At first I was going to suggest this be split into 2 *entries* (not just senses, as discussed on 紡ぎ糸).

But after a lot of reading, I don't think 紡ぎ is generally used as "pongee" or tsumugi. The high n-gram occurences are for spinning-related activities.  reverso hits are all "spinning", wikipedia in English/Japanese list only 紬.  The cleanest/simplest thing to do, without dictionary support suggesting otherwise (daijs doesn't), is to just [sK] it, or remove it entirely. 

Also, the [expl] would appear to be off.  sankoku specifically mentions the fabric being tough (あらい手ざわり, and not especially thin), and English wikipedia notes the same several times.  Originally this was a low-grade silk product used by peasants.

If I understand correctly, this is not a particularly obscure term.  If you see a picture of the cloth, you might remember the texture yourself if you've ever handled such a fabric (in a kimono, etc).

@@ -10,0 +11 @@
+<ke_inf>&sK;</ke_inf>
@@ -18,0 +20 @@
+<gloss>tsumugi</gloss>
@@ -20 +22 @@
-<gloss g_type="expl">soft thin cloth woven from raw silk</gloss>
+<gloss g_type="expl">traditional rough-surfaced cloth woven from silk</gloss>

tidying

@@ -19 +19,2 @@
-<gloss>pongee (soft thin cloth woven from raw silk)</gloss>
+<gloss>pongee</gloss>
+<gloss g_type="expl">soft thin cloth woven from raw silk</gloss>