Delete a string after certain symbol SQlite

I have a dictionary database with table called "eng" and column called "defn". Data in "defn" is like that:

/(v5r,vt) (uk) to pluck/to pick/to tear off

/(n) (uk) (See ほぞ穴) tenon/cog/dovetail/pivot

/(adj-no) bilingual/in two languages

What I need is to delete all the symbols after first ")". Result must be something like that:

/(v5r,vt)

/(n)

/(adj-no)

I was thinking about using the SUBSTR but the problem is that in each line length of word inside the "()" is different. And /(some word) exist in each string of the column.

Couldn't someone kindly suggest me the best way to do it? Thank you in advance.