What is the ruling on saying: "He seems to have a bit of a heavy disposition (dullness)" about someone, and is this considered backbiting if the speaker's intention was not mockery?

Backbiting: Mentioning about your brother what he dislikes. So, if the mentioned statement indicates a disparagement that the person dislikes, then it is backbiting. Repentance to Allah is obligatory for it, and seeking forgiveness from the person by asking for pardon and forgiveness, if possible, without causing harm. If seeking his forgiveness leads to harm, then one should seek general absolution without specifying the right. Some scholars believe that it is sufficient to seek forgiveness for the one who was backbitten, praise him, and mention him with goodness.