The word reticent is an adjective.
"Reticent" is the adjectival form of the noun "reticence".
Adjective
This is my favorite class. This class is my favorite.
The word class 'noun' is a very large open word class. Open means new words can be added to it. For example words like internet, wikipedia are recent nouns. Many word classes are closed for example the word class 'articles'.
onomatopoeia
She has always been reticent about discussing her private life. Because of nearly drowning as a child, he's reticent about attending a pool party. A mouth full of fillings makes her reticent to chew gum and eat sticky foods. After a student made laughed at him, Jeff was reticent to volunteer another answer in class.
The suspect was reticent to answer the question because he did the crime.
Reticent
The word you are looking for is "reserved".
Reserved or reticent.
Uneffusive. Reticent. Reserved. Withdrawn. Timid
(adj.) - disinclined to speak; restrained or reserved in style
I was reticent about revealing the source of my information. OR She was never reticent about her dislike for country music. OR He was reticent to tell the truth for fear he would be punished.
The root word of reticence is "reticent," which comes from the Latin word "reticentia," meaning silent or reserved.
In Germany people were reticent; if they did talk they could be put to death.
A sentence with the word 'reticence': His reticence made him lonely and a less friendlier person.
means reserved and unwilling to communicate. The man was reticent when his wife died.