Refers to a card that has the following conditions fulfilled:

Hypermaxing a card does not require it to have a full set of latent awakenings, nor does it require it to be assisted, as shown below:

https://cdn.discordapp.com/attachments/337833568468336643/584290026515333159/Screenshot_20190601-005948_PAD.jpg
Romia is Fully Leveled, Plussed, Awoken, and Skilled Up! This qualifies as her being hypermaxed; even though she lacks 3 Latent Awakenings and an assist.

See also