The term 'capable of being sustained' can be broken down into five different crossword solutions: sustainable (11 letters), tensile (7 letters), isolable (8 letters), VINCIBLE (8 letters), and SOLUBLE (7 letters). Sustainable refers to something that can be maintained at a certain level or rate for an extended period of time. Tensile means having the ability to be stretched or pulled without breaking. Isolable is the ability to be separated or isolated from other things. VINCIBLE is the opposite of invincible, meaning something can be conquered or defeated. Lastly, SOLUBLE means something that can be dissolved in a liquid.