The five abstentions

A distinctive feature of Yom Kippur is its designation in the Torah as both a 'Sabbath' and a fast day. Fasting on Yom Kippur (from before sunset until after dark the following night), which the Torah expresses with the term ‘affliction,’ is a broader concept than a mere abstention from food and drink. The Sages (see Yoma 76a-77b) derive from Biblical exegesis that affliction implies abstention from five activities: 
(a) eating and drinking; 
(b) washing one's body; 
(c) anointing oneself with oils; 
(d) wearing leather shoes; and 
(e) marital relations. 
 In addition, all labors that are forbidden on the Sabbath are forbidden on Yom Kippur as well. 
 (from Artscroll)