To Suffocate; Cover Something Until It’s Airtight
Puzzle 3 of Buying Books Piece of Cake Pack
Question is: To Suffocate; Cover Something Until It’s Airtight
and the answer is: SMOTHER
Word Meaning:
SMOTHER — (transitive) To suffocate; stifle; obstruct, more or less completely, the respiration of something or someone.
Definitions from Wiktionary.