General Opposites:
* Retain: To keep or hold onto something.
* Keep: To continue to possess or have something.
* Claim: To state that something belongs to you.
* Acquire: To gain possession of something.
* Hold on to: To refuse to give up something.
* Cling to: To refuse to let go of something, often out of fear or desperation.
Specific Opposites:
* Assume: To take possession of something, often a responsibility or role. (Opposite of relinquishing a position or responsibility)
* Maintain: To continue to have or possess something. (Opposite of relinquishing control or ownership)
* Protect: To keep something safe from harm. (Opposite of relinquishing a valuable possession)
* Fight for: To actively work to keep something. (Opposite of relinquishing a right or privilege)
The best opposite word will depend on the specific situation and the meaning of "relinquish" in that context.