The Collaborative International Dictionary of English v.0.48:
Relinquishment \Re*lin"quish*ment\ (-ment), n. The act of relinquishing. [1913 Webster]WordNet (r) 3.0 (2006):
relinquishment n 1: a verbal act of renouncing a claim or right or position etc. [syn: relinquishment, relinquishing] 2: the act of giving up and abandoning a struggle or task etc. [syn: relinquishment, relinquishing]