This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

v. Simple past tense and past participle of sustain.

adj. held continuously at a certain level

adj. held at a certain pitch

adj. Held up to a certain pitch, degree, or level; uniform.

Kept up or maintained uniformly, as at one pitch or level, especially a high pitch, or at the same degree, especially a high degree.

In heraldry, same as supported: see also surmounted.

adj. maintained at length without interruption or weakening

adj. (of an electric arc) continuous

"Khalid bin Ahmed Al Khalifa said the Gulf force is needed to counter what he called a sustained campaign'' by Iran in Bahrain."

continuous    uninterrupted   

sustained note    tone   

uniform    continued    constant   

sustain   

Refrained    abstained    arraigned    ascertained    attained    brained    campaigned    caned    chained    complained