If "clasp" refers to a fastening device:
* Unclasp: This is the most direct opposite, meaning to release a clasp.
* Open: This is a broader term for making something accessible.
* Unfasten: This is another general term for releasing a fastening.
If "clasp" refers to the act of holding onto something tightly:
* Release: This means to let go of something.
* Loosen: This means to make a grip less tight.
* Let go: This is another way to say "release."
If "clasp" refers to an embrace:
* Push away: This means to physically move away from someone.
* Ignore: This means to refuse to acknowledge someone.
* Reject: This means to refuse to accept someone.
To determine the most appropriate opposite, consider the specific context in which you are using the word "clasp."