Inflation is the gradual increase in the costs of goods and services over time.
Very high inflation is extremely damaging for an economy and economists generally believe that very low or zero inflation is also damaging.
Adjusting any metric for inflation means removing the effects of inflation from that price.
This allows a 'real' change in that value or price to be assessed over time.
In our blog: 'The UK Housing Market Since the Mini Budget', we compare the changes in the housing market since the mini-budget in absolute (unaltered) and real (inflation adjusted) terms.