Highly-skilled emigration

WordNet Word definitions in WordNet
n. depletion or loss of intellectual and technical personnel

Wikipedia Word definitions in Wikipedia
Brain Drain is a fictional character appearing in American comic books published by Marvel Comics . The character first appears in Invaders #2 (Oct. 1975) and was created by writer Roy Thomas and artist Frank Robbins .

Wiktionary Word definitions in Wiktionary
n. The migration of educated or talented people from less economically advanced areas to more economically advanced areas, especially to large cities or richer countries.

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
noun EXAMPLES FROM CORPUS ▪ He could not argue, looking at Imperial, that there has been a major brain drain of senior staff.