Opposite meaning of 'Hermetic' is -

• Hermetic (adjective)
English Meaning: (of a container) so tightly closed that no air can leave or enter.
Bangla Meaning: সম্পূর্ণরূপে বাতাভেদ্য: a hermetic seal; দুর্বোধ্য; a hermetic poem.

Synonyms: Sealed (চতুর্দিক বন্ধ করে দেয়া/ভালোভাবে বন্ধ করে দেয়া), Deep (গভীর), Shut tight (আঁটসাঁট), Profound (প্রগাঢ়), Recondite (পূননির্মান)।

Antonyms: Open (খোলা), Easy (সহজ), Shallow (অগভীর), Simple (ভাসা ভাসা) Ajar (ঈষৎ খোলা), Straightforward (অকপট, সোজাসুজি)।

Example Sentence:
1. Lids are attached using the company's Ultra seal technology, which produces a hermetic seal in less than 2 seconds.
2. Efforts to keep that hermetic seal are getting more desperate.

Source: Website Lecture.