Self-sealing is a term that refers to the ability to seal or close on its own, without the need for any external force or aid. Synonyms for this word include airtight, watertight, hermetic, self-closing, and self-locking. These words describe the same characteristic of being able to automatically seal or shut without requiring human intervention. While self-sealing is commonly used in industries such as aerospace, automotive, and packaging, the synonym options provide a broader range of words that can be used interchangeably in different contexts. Hence, depending on the intended context, these synonyms offer an excellent alternative to the term "self-sealing".