Schedule this month one absolutely fixed

• Unchanging, those full of beans, say in early part of tennis match?
• When troubled, is not tense or rigid
• Fixed, unalterable

Wikipedia Word definitions in Wikipedia
Set in Stone may refer to:

WordNet Word definitions in WordNet
adj. no longer changeable; "the agreement is not yet set in stone" [syn: carved in stone ]

Wiktionary Word definitions in Wiktionary
(context idiomatic English) permanent; certain; firm v to make permanent, certain, or firm