This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
諓 combines 言 (speech) with 戔, which likely contributes sound. The exact historical development is uncertain.
With 言 (speech) on the left and 戔 on the right, 諓 might suggest words that are small or petty, but its meaning is too uncertain for a reliable mnemonic.
For セン, imagine a cent (coin) being talked about in petty speech: cent -> セン, and the speech radical 言 hints at the meaning.