WordNet (r) 3.0 (2006):

time and a half
    n 1: a rate of pay that is 1.5 times the regular rate; for
         overtime work

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "time and a half":
   Trinkgeld, bonus, bounty, bribe, consideration, donative,
   double time, fee, gratuity, gravy, grease, honorarium,
   incentive pay, inducement, lagniappe, largess, liberality,
   palm oil, perks, perquisite, pourboire, premium, salve,
   something extra, sportula, sweetener, tip