This is the 12316th most frequent Polish word.
mobilną
The Polish word "mobilną" means "mobile" in English, referring to something movable or portable.
Here, "mobilną" is used to describe an application that is mobile—that is, suitable for use on mobile devices such as smartphones or tablets.
Mam mobilną aplikację do nauki języków.
I have a mobile app for learning languages.
In this sentence, "mobilną" refers to a website that is optimized for mobile access, typically with design adjustments for smaller screens and touch interfaces.
Zaprojektowałem mobilną stronę internetową.
I designed a mobile website.
Here, "mobilną" is used to signify that the speaker wishes for a version of the software that can be used on mobile devices.