How to use <lightning:select> on Community? PURE Markup, no APEX, no JS

You are not specifying the required attributes in your component as stated in the documentation:

Attribute Name ----- Attribute Type --------- Required?

label -------------- String ----------------------- Yes

name -------------- String ----------------------- Yes

<lightning:select name="selectItem" label="Select an item">
    ...options...
    </lightning:select>