The phrase "wash one's hands of" reflects the action of disassociating oneself from a matter or problem. The opposite of this phrase could be the expression, "roll up one's sleeves," which signifies getting one's hands dirty and taking responsibility for a situation. Another antonym for washing one's hands of could be "embracing," which implies taking a vested interest in the matter at hand. Likewise, some other synonyms could be "engage," "support," or "assist," suggesting an active and involved approach to resolving the issue. Overall, these antonyms present a sense of accountability and a willingness to tackle challenges rather than ignoring or avoiding them.