Allyship in this context is when someone with racial privilege joins those who are racially disadvantaged to help dismantle racism. Because “ally” suggests mutual benefit and support, some prefer alternative descriptors for a racially privileged person challenging racism, such as “someone acting in solidarity,” “accompanier,” “co-conspirator” or “accomplice.”
Racial colorblindness is the idea that we should ignore racial differences in order to combat racism. Though colorblindness is often a well-intentioned approach to dealing with racism, it overlooks the reality of the different life experiences people have based on their race and fails to celebrate the benefits of having difference in our society.
Racism is a deeply-rooted system in our country that disadvantages and devalues people of color as a group and advantages and empowers white people as a group. Racism is also individual instances of hatred, prejudice or discrimination by a person in a dominant racial group directed at a person of a marginalized racial group.
White fragility is “a state in which even a minimum amount of racial stress becomes intolerable, triggering a range of defensive moves. These moves include the outward display of emotions such as anger, fear, and guilt, and behaviors such as argumentation, silence, and leaving the stress-inducing situation. These behaviors, in turn, function to reinstate white racial equilibrium.” - Robin DiAngelo
White privilege is unearned advantage based solely on the color of white skin. There are many other forms of privilege (i.e. gender, class, sexual orientation, etc.) but white privilege exists if you have white skin, regardless of your other social identities.