What is the meaning of words like "Shalikhuna" and "Mashtaba" that are mentioned in the Hizb Taskhir al-Qulub attributed to Al-Jilani, and is it permissible to utter them?

Allah has commanded us to invoke Him by His Most Beautiful Names. It is considered a deviation (ilhad) to name Him with names not mentioned in the Quran and Sunnah, and this is impermissible. Every act of worship not brought by the Messenger of Allah, peace and blessings be upon him, is rejected. Dhikr (remembrance of Allah) is a great act of worship. Scholars have compiled authentic hadiths concerning adhkar (forms of remembrance). What has been authentically reported from the Prophet, peace and blessings be upon him, is sufficient for every person who remembers Allah. Therefore, we advise adherence to the Prophetic Sunnah.