occasional
oc.ca.sion.al \-'ka-zh-n*l, -*n-*l\ \-e-\ aj 1: occurring or operating on a particular occasion 2: acting as the occasion or contributing cause of something 3: composed for a particular occasion {~ verse} 4: met with, appearing, or occurring at irregular or rare intervals 5: acting in a specified capacity from time to time 6: designed or constructed to be used as the occasion demands - oc.ca.sion.al.ly av