What do the following words have in common that is hinted at by the last clue?

1. Agitate

2. Whiten

3. Gravity

4.Visitor

5. Subtitle

6. Composite

7. Becoming senile

Answer:

 

Answer to clue 7: 

Losing it

 

Each clue word remains a valid word after "it" is removed:

 

1. Agitate - agate

2. Whiten - when

3. Gravity - gravy

4. Visitor - visor

5. Subtitle - subtle

6. Coposite - compose