Some consider the usage of false cognate to mean "false friend" to be incorrect.
Examples of false cognates:
Many completely unrelated languages use some variant of ma for "mother".
English have (and the related German verb haben) and Latin habeō are false cognates — have is rather cognate to capiō.
English island and isle are false cognates. Island is derived from old English igland and isle is derived from Latin insula, via Old French.
Spanish atender and English attend are indeed cognates (they have a shared root in the Latin attendere), but they are false friends (they have different meanings, as atender means "assist, look after"), thus, they are only false cognates in the second sense. Coincidentally, there is another pair of false friends with meanings vice versa: Spanish asistir and English assist mean "attend" and "assist," respectively.