Where does “अलंकृ” come from?

अलंकृ (Sanskrit) comes from Sanskrit कृ, from Proto-Indo-European kʷer- — to do; to make; to build.

Ancestry of “अलंकृ”, step by step

Step	Language	Word	Meaning
1	Sanskrit	कृ	to make
2	Proto-Indo-European	kʷer-	to do; to make; to build