Although there is no proof for it, there is allusion
Although there is no conclusive proof for the matter, there is some support or hint that can be relied upon. Even if there is no proof, there is something or an allusion to it.
("From where do we know that anointing is like drinking on Yom Kippur? Although there is no proof for it, there is allusion, as it is said (Psalms 109), 'Let it come into his inward parts like water, and like oil into his bones.'" - Shabbat 9b)
Translation
Expression (Hebrew)
אַף עַל פִּי שֶׁאֵין רְאָיָה לַדָּבָר זֵכֶר לַדָּבָר
Definition (Hebrew)
אַף עַל פִּי שֶׁאֵין זוֹ הוֹכָחָה חוֹתֶכֶת לַנּוֹשֵׂא, הֲרֵי שֶׁיֵּשׁ סִיּוּעַ אוֹ רֶמֶז כָּלְשֶׁהוּ שֶׁנִּתָּן לְהִסְתַּמֵּךְ עָלָיו. גַּם אִם אֵין הוֹכָחָה יֵשׁ מַשֶּׁהוּ אוֹ רֶמֶז לְכָךְ.
("מִנַּיִן לְסִיכָה שֶׁהִיא כִּשְׁתִיָּה בְּיוֹם הַכִּפּוּרִים אַף עַל פִּי שֶׁאֵין רְאָיָה לַדָּבָר זֵכֶר לַדָּבָר שֶׁנֶּאֱמַר (תְּהִלִּים קָט) וַתָּבֹא כַמַּיִם בְּקִרְבּוֹ וְכַשֶּׁמֶן בְּעַצְמוֹתָיו"- שַׁבָּת ט ד)