In this usage, the term means difficult to guess. An encryption algorithm is intended to be unbreakable (in which case it is as strong as it can ever be), but might be breakable (in which case it is as weak as it can ever be) so there is not, in principle, a continuum of strength as the idiom would seem to imply: Algorithm A is stronger than Algorithm B which is stronger than Algorithm C, and so on.
Smart Clothing is made from fabrics that are wireless and washable that integrate computing fibers and materials into the integrity of the fabrics. Georgia Tech is one university among several, which include MIT and University of California at Davis, that conduct research in the area of intelligent fabric.
The apparel that we wear is more than simply about style, color, and fit. The clothing that we wear must be trendy & comfortable, but it also must be made of proper quality. Nothing is worse than purchasing clothing in the perfect color, only to find that after you washed it the color changes.