A melt-spun synthetic fiber and process for producing the fiber are described, the fiber including a fiber-forming synthetic polymer and a siloxane-based polyamide with a repeating unit having the formula (I) ##STR00001## wherein n is a number in the range of 1-500 inclusive and specifics the number of repeating units of the siloxane-based polyamide, DP is the average degree of polymerization of the siloxane component of the siloxane-based polyamide and is in the range of 1-700 inclusive, X is selected from the group consisting of linear or branched alkylene chains having 1-30 carbon atoms, Y is selected from the group consisting of linear or branched alkylene chains having 1-40 carbon atoms, and each of the R.sup.1-R.sup.4 groups is independently selected from the group consisting of methyl groups, ethyl groups, propyl groups, isopropyl groups, siloxane chains, phenyl groups, and phenyl groups that have been substituted with 1-3 members selected from the group consisting of methyl groups and ethyl groups.