«لِفُلَانٍ عَلَيَّ شَيْءٌ»
“I owe so-and-so something.”
Shay’ (“something”) does not disclose the object of the obligation. There is an admission, but neither the particular class nor the precise item has been identified. If the speaker subsequently clarifies that the thing is a garment, the further words provide tafsir of the initially unspecified expression.
The distinction has a legal consequence: until the object is identified, the nature of performance, liability or claim cannot be determined precisely. Tafsir gives operative content to words whose intended object was initially concealed.