In layman's terms, bitcoin is currently (and probably will always be) deflationary, because the demand for bitcoins is increasing much faster than the supply, and as the value of a bitcoin increases, the prices of goods decrease.
Actually, over the recent few months, bitcoin has been inflationary both in economic terms AND layman's terms.
http://bitcoincharts.com/charts/bitstampUSD#rg180zigHourlyzczsg2013-11-29zeg2014-05-09ztgSzm1g10zm2g25
