Senectitude, anility, feebleness, caducity, dotage, decrepitude...
Words synonymous to the term "biting" are chomping, itching, and nipping. Other synonymous words include stinging, marking, burning, pinching, and wounding.
stratificationstructurealphabet
danger
The phrase "alteration" can be synonymous with changing in Sonnet 116.
With what? Synonymous means that something has the same meaning, so you have to be more specific. Some slang words mean the same as other words, but some don't.
pomp, pomposity, splendor
The words fluid and unstable are synonymous.
Yes, those words are synonymous.
The best way to prevent senility is to make the brain work. Word games, memory puzzles, sudoku are all methods to keep the brain cells alert. Senility may be genetic but it can be delayed.
Opposite, reverse...
Yes, those words are synonymous.
obedient