Used to choose freely from a group, without caring which one
Encoding Strategies:
linguistic

cual
whichever one
+
quiera
[someone] may want
Cualquiera is usually translated as any and literally means "whichever one someone may want," as in any one you want.
cualquiera
any, any one, whichever
Used to pick something when the specific choice doesn't matter. Any one is acceptable, choose whichever one you want.
Puedes sentarte en cualquiera de esas sillasYou can sit in any of those chairs
Elige el que quieras, cualquiera funcionaPick whichever one you want, they all work
anyone, whoever, whichever (when followed by "que")
When followed by "que," it means anyone or whatever thing that meets a condition. Choose any one that...
Cualquiera que quiera puede unirse al grupoAnyone who wants can join the group (anyone that wants can join the group)
Cualquiera que elijas va a quedar bienWhichever you choose will look great (any that you choose will look great)
ordinary, just any, random (dismissive)
When placed after the noun, it takes on a dismissive tone. "Just any old one," not special or remarkable in any way.
No es un restaurante cualquiera — tiene estrella MichelinIt's not just any restaurant — it has a Michelin star
Me dio una respuesta cualquiera y se fueHe gave me some random answer and left
un cualquiera / una cualquiera
a nobody, a nobody of importance (derogatory)
Describes someone of no importance or standing. Just any random person, nobody special.
No voy a dejar que un cualquiera me diga cómo hacer mi trabajoI'm not going to let some nobody tell me how to do my job
El premio lo ganó un cualquiera que nadie conocíaThe prize was won by a nobody that no one knew
tramp, loose woman (derogatory, feminine)
An insult for a woman that implies she's available to any man. She'll go with whichever one wants her.
La llamó una cualquiera delante de todosHe called her a tramp in front of everyone
No me vengas con esas, no soy una cualquieraDon't come at me like that, I'm not some loose woman