Skill
ability
Ability
Bravery.
Unusual is a synonym for not ordinary.
Antique has a synonym of obsolete. Obsolete has a synonym of outmoded. Since outmode is a transient verb it is always conjugated. But outmode is a word, it is 7 letters and it is a synonym for antique.
A prefix is an affix placed before the root of a word. There is no 7-letter prefix for "unworthy". A synonym is a word with a similar meaning. Some 7-letter synonyms for "unworthy" are beneath, nothing & ignoble.
"SIAMESE", although I'm not sure it's politically correct.
painful
If you mean a gesture/action/sound to convey information then, Message, gesture or warning
The only 7-letter synonym for peace (the answer to this question) may be harmony. But it does not represent an actual period of time as peace does.
A 7 letter word for an unproven belief is an opinion. An opinion is something that you think and believe but either cannot or have not factually proven.
The word Mollusk is a 7 letter word.
In the King James version the word - skilful - appears 7 times the word - skilfully - appears once the word - skilfulness - appears once the word - skill - appears 7 times
The 7 letter word is "Capsule"