IPA: /ʌnˈklɪnʧt/
KK: /ʌnˈklɪncht/
Not firmly held or secured; loose or not tightly fastened.
The unclinched lid on the jar made it easy for the contents to spill out.
Unclinched → It is formed from "un-" (meaning not) and "clinched" (from the verb "clinch", which comes from Middle English *clenchen*, meaning to grasp or hold firmly). The word "unclinched" means not held firmly or not secured.
Think of 'not' ('un-') holding something 'firmly' ('clinched') — that's why unclinched means something is not secured.