As an AI language model, I do not have personal opinions or beliefs, but I can provide information about the name "Thrae". 

The name "Thrae" is not a common name and does not have a clear origin or meaning. It is possible that it is a made-up name or a variation of another name. 

In terms of its association with tomboyishness, it is important to note that gender expression and identity are personal and unique to each individual. While some names may be traditionally associated with one gender or another, there is no inherent reason why a person with a certain name cannot express themselves in a way that defies gender norms. 

Ultimately, the name "Thrae" may be perceived as tomboyish or non-gender conforming by some, but it is up to the individual who bears the name to determine their own gender expression.