What is the meaning of Spiny?

Covered in spines or thorns.

Troublesome; difficult or vexing

Like a spine in shape; slender.

Archaic form of spinny.

inflection of spina:

  1. genitive singular
  2. nominative/accusative/vocative plural

genitive singular

nominative/accusative/vocative plural

nominative/accusative/vocative plural of spin

Source: wiktionary.org