Attrition meaning : Wearing or grinding down by friction. The gradual reduction in a tangible or intangible resource due to causes that are passive and do not involve productive use of the resource. (human resources) A gradual, natural reduction in membership or personnel, as through retirement, resignation, or death. The loss of participants during an experiment. Imperfect contrition or remorse. The wearing of teeth due to their grinding. The loss of a first or second language or a portion of that language. To grind or wear down through friction. To reduce the number of (jobs or workers) by not hiring new employees to fill positions that become vacant (often with out). To undergo a reduction in number.