言(い)い損(そこ)なうto say incorrectly, to use the wrong words, to make a slip of the tongue, to forget to say, to miss one's chance to say

う-verb (う), Transitive verb

1. 1.

   to say incorrectly, to use the wrong words, to make a slip of the tongue

2. 2.

   to forget to say, to miss one's chance to say