«وإن كان بالجنس البعيد والفصل القريب أو به وحده يسمى حداً ناقصاً»
If it uses the remote genus with the proximate differentia, or the proximate differentia alone, it is called an incomplete essential definition.
Example 1: الإنسان جسم ناطق
The human is a rational body.
Example 2: الإنسان ناطق
The human is rational.
In both cases the essential distinction is conveyed, but the full pair required for a complete essential definition is absent. The first uses a remote genus; the second does not mention a genus.