أن يقع التعليل بحكم شرعي لا لأمر لغوي
The effective cause must rest on a legal ruling, not simply on a linguistic relationship.
Two things may share a name or verbal root without sharing every legal consequence. Rules of Islamic law depend on recognized scriptural and juristic indications, not ordinary dictionary equivalence alone.
Practical distinction: Two activities may both be called 'movement' or 'contact' in everyday speech. That common label cannot by itself establish a shared legal cause. The link between the relevant attribute and the ruling must be supported by legal evidence.
Language helps identify meanings; it does not on its own create a legally effective cause.