I have worked in the cybersecurity division of my employer in the United States for about 9 years with last 4 years, in a management role.
I have a female colleague whom I know well , and is also in a management role, albeit at a lower level than I am (team lead , 6 direct reports for her). While I am older than her, age difference is only 4 years apart. I don't supervise her in any way, but we do share a N+2 skip level manager.
Today, a project we were both involved in was completed and stakeholders gave us excellent feedback. I said to my colleague: Nice work, girl! and you really are a team player, girl meant to compliment her for work well done. Again, we know each other well, so I did not think much of it.
My intent is that girl in this context is not meant to be taken literally as derogatory substitute for her true name, but rather an informal greeting / acknowledgement between good friends. However, a separate colleague in my team pointed out to me that girl in the way I used it could be perceived to be derogatory and condescending , as if my colleague was of lesser worth, and diminishing her status. My intent was never to be malicious or rude
Is the word girl in above context rude and unprofessional?
If so, should I apologize to her or is ignoring but being more mindful in future the better option?
Note: English is my second language but I have lived in US for close to 30 years and am a citizen. I am male.