Is Bitcoin deflationary and inflationary at the same time? I was wondering as Bitcoin is represented in the public and media as a deflationary currency (for more adept media as payment protocol). Is it really deflationary?

Deflation is described on Wikipedia as:


  In economics, deflation is a decrease in the general price level of goods and services ...
  This allows one to buy more goods with the same amount of money over
  time.


Inflation is described on Wikipedia as:


  Economists generally believe that high rates of inflation and hyperinflation are caused by >an excessive growth of the money supply.


At the moment there is really an excessive growth of Bitcoin supply - in the past 4 years there was mined over 12 millions of bitcoins and will continue
 with every block rewarded by c. 2140 when all bitcoins are expected to be mined. So there will be only transaction fees as block rewards, which will  end the growth of the units supply. 

Can we consider Bitcoin as inflationary and deflationary currency until 2140, because there are still new bitcoins generated until c. 2140?
The keyword is "excessive".

Inflation can be related to the supply of money with the quantity theory of money:  

MV = PQ  

Where M is the supply of money, V is the velocity of money, P is prices, and Q is production, all taken as the temporal quotient thus geometrically added. 

Prices can only go up or down.  Judging by the exchange rate, prices in terms of BTC are deflating as no one would pay 3 BTC for a gallon of gasoline as they would at the beginning of 2012 or so; now, they would pay 0.0003 BTC.

Price are deflating because demand for bitcoin is rising as evidenced by the skyrocketing velocity.

So even though the supply is growing, it is not excessive because velocity is growing so much faster.  Actually, the supply of bitcoin should've grown faster during this period, but it is not programmed to do that.

No cryptocurrency is currently programmed for perfect price stability.