1. That can not be satisfied.

2. Insatiable.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• 7nsatiable,
• ubsatiable,
• umsatiable,
• ujsatiable,
• uhsatiable,
• unaatiable,
• unzatiable,
• unxatiable,
• undatiable,
• uneatiable,
• unwatiable,
• unsztiable,
• unsstiable,
• unsatiabke,
• unesatiable,
• unsatiablwe,
• unstiable,
• unsatiabl,
• unsataible,
• unsatiablly

• ungetatable,
• unsatiably,
• unsaturated,
• unagitated,
• unstirred,
• unactable,
• unstated,
• unsatisfied,
• unstratified,
• uncoated,
• unquotable,
• unsatisfying,
• unsatisfiable,
• unstilted,
• unsatiated,
• unsated,
• unstable,
• unstinted,
• unsuitable.

The adjective form of the word "unsatiable" is "insatiable".

The plural form of the word "unsatiable" is "unsatiables".

The singular form of the word "unsatiable" is "unsatiable". There is no change in form between singular and plural.