Definitions for unhindered
Random House Webster's College Dictionary
not slowed or blocked or interfered with
"an outlet for healthy and unhampered action"; "a priest unhampered by scruple"; "the new stock market was unhampered by tradition"
Not hindered, slowed, blocked or hampered.
Pertaining to a molecule where the reactive center is not blocked from chemical attack due to the surrounding uncreative substituents not preventing reactive agents accessing the reactive site.