na-adjective, noun
weak legs; slow walker
Describes a person whose legs are weak or who walks slowly. Often used as a noun or adjectival noun.
祖母は足弱で、ゆっくりしか歩けない。
My grandmother has weak legs and can only walk slowly.
彼は足弱だから、遠出は無理だ。
He's a slow walker, so long trips are out of the question.