What is the cold version of spicy?

Solution 1:

The technical term for the feeling you get from menthol and associated compounds is "cool" and variants, like "cool mouthfeel" or "cooling sensation"

You can see in those technical catalogs for artificial cooling agents how the sensation is described

Example 1 - Symrise

Example 2 - ABT

It can even be used for the effect it creates on the skin like in Example 3 - Takasago

Note that sometimes you can experience a sensation that is more similar to "spicy" than it is to "cool" in some products due to how they're formulated (usually because of the presence of other agents that might irritate the mucous membranes in your mouth, like alcohol, eucalyptol, methylsalicilate...) but I digress.

Solution 2:

'Spicy' in English -usually- refers to the heat in a hot pepper coming from capsaicin. Sometimes 'spicy' is also used to refer to a strong savory taste, like what you get from black pepper (old world pepper which is not the same as the chili peppers from the Americas). But spicy more often refers to things measurable on the Scoville scale.

'Mintiness' is what you get from the mint, an aromatic chemical called menthol. It is unrelated chemically to capsaicin, and the human tongue receptors are different.

In European gastronomy there is an understood difference between the -noun- 'spice' and the noun 'herb'. 'Herbs' are flavorings coming from leaves, and spices are everything else (eg salt from minerals, cinnamon from bark, capsaicin from seeds). So mint is an herb whereas capsaicin is a spice.

A synonym of spicy in English is hot and aromatics like menthol do have a cooling sensation but really they just aren't opposites. One might use

'cool' or 'refreshing'

as a counterpart to 'spicy'. You might also just use these for for mint but you would also just say

'minty'.