«وَإِمَّا بِالتَّتْمِيمِ، وَهُوَ أَنْ يُؤْتَى فِي كَلَامٍ لَا يُوهِمُ خِلَافَ الْمَقْصُودِ بِفَضْلَةٍ»
Tatmīm is an added constituent in speech that does not itself suggest a contrary, unintended meaning.
The purpose of tatmīm is not to guard against a misleading inference, but to enrich an already intelligible assertion with an appropriate descriptive or qualifying element. The core statement remains meaningful without that element; the addition increases the statement's precision, force, or expressive value.