correspond to, proportionate to, conform, imitate
凖 centers on matching or aligning with a standard: corresponding to something, being proportionate, conforming, or imitating a model.
凖 is a variant form of 準. The standard form 準 combines 氵 (water) with 隼, which likely contributes the sound and the idea of a level or standard. The variant 凖 replaces 氵 with 冫 (ice), but the historical reason for this variation is uncertain.
The top 准 suggests approval or a standard, and the bottom 十 (ten) can represent a perfect score. Imagine a ruler checking that everything conforms exactly to the approved standard.
For ジュン, picture a judge in June checking that everything conforms to the rules: June -> ジュン.