This is the 9883rd most frequent Japanese word.
詮
"詮" means "investigation," "reason," or "conclusion."
In this context, '詮' refers to the gist or main point being investigated.
問題の詮を突き止める必要があります。
It is necessary to determine the crux of the issue.
Here, '詮無い' implies futility, showing '詮' as part of a negative adjective.
結局、詮無い議論だった。
In the end, it was a pointless discussion.
'詮索' combines '詮' with '索', meaning to inquire or scrutinize.