This is the 954th most frequent Arabic word.
شخصا
A person or someone.
The word 'شخصًا' refers to an undefined individual, functioning as the direct object of the verb 'رأيت' (I saw).
لقد رأيت شخصًا في الحديقة.
I saw someone in the park.
The word 'شخصٍ' refers to a single undefined individual, in the sense of capacity, following the preposition 'ل' (for).
هذا المكان يتسع لشخصٍ واحد فقط.
This place can accommodate only one person.
The word 'شخصٍ' is used to refer to every individual in a general sense, functioning as the subject of the verb phrase 'يجب أن يتحمل' (must assume).