Collins Chinese Dictionary Plus (3rd edition), 2011:
任意 rènyì
I 副
at will
- 你可以任意指派一个(個)人做这(這)件事。 Nǐ kěyǐ rènyì zhǐpài yī gè rén zuò zhè jiàn shì. You can send anyone you like to do this job.
II 形
unconditional