Style of women's clothing designed to project confident efficiency (5,8)
I believe the answer is:
power dressing
(Other definitions for power dressing that I've seen before include "Professional women's fashion style, designed to project authority" , "Style of female business wear designed to establish authority" , "Style perhaps adopted by women executives" , "Wearing of severely tailored suits by some women executives" , "(Of women) donning clothes to look authoritative" .)