na-adjective, noun
loose; immoral; dissolute; licentious
Describes a person's sexual conduct or lifestyle as lacking moral restraint; often used for promiscuity or debauchery.
彼はふしだらな生活を送っている。
He leads a dissolute life.
ふしだらな関係が噂になっている。
Their immoral relationship is the subject of gossip.
na-adjective, noun
Refers to a person's appearance, dress, or habits being careless and unkempt; less common than the moral sense.
彼女はいつもふしだらな格好で出社する。
She always comes to work looking slovenly.
The origin is uncertain. It may be related to the mimetic word ふし (as in ふしだら) suggesting something loose or slack, but the exact derivation is unclear.