The Mem has several meanings; water, people, nations, languages, and tongues. As for Jesus, it shows Him as the Living Water.
The Nun has to meanings, the faithfulness and the reward of faithfulness. In Aramaic the word Nun means life. Joshua the Son of Nun (Son of Life) is the one who took Moses’ place and led the Children of Israel into the Promised Land. A type of Jesus.
The root word for Samekh means; to lean upon, uphold, or support. It is the Jewish concept of laying the hands on a sacrificial animal.