We have, it would seem, been blaming each other since the dawn of time. People never change at heart. This modern word came into English in around 1200, and at that time it meant “to criticise, to find fault with” – the concept of blaming as in “accuse of being at fault, of being responsible for” developed over the next century, as can be seen in this example from 1325:
Yat yu on me hafs layt thys blam..Y led my lyf wit godis loue.
(Yet you have laid this blame on me. I led my life humbly)
(Middle English Humorous Tales in verse, the Interlude of the Clerk and the Girl, 1325)
It came from Old French blasmer, which meant “to criticise”, but was also used to mean “rebuke, tell off”. This has developed into blâmer in Modern French. In neither language has it come a long way since then, but let us take a look at where Old French took it from, to see the its earlier forms and meanings.
It derived from Late Latin, or Church Latin blasphemare, which meant “revile”. You may think the form looks familiar, and indeed this is where the word blaspheme comes from, making it a modern cognate of blame.
The Latin word does not start its story here – it came from Greek βλασφημώ (blasfimo/ vlasfimo), which meant “slander”or “speak evil of”. It is made of two elements joined together: βλάπτω (vlapto) and φημώ. The first part, βλάπτω, means “harm”, and it is the imperfect stem έβλαψ- (evlaps) that gives us the /s/. The second element, φημώ, meant “say”, thus making the compound word “speak-harm”. Interestingly, the English word fame comes from the same root as φημώ, via Latin fama.
So, from “speak-harm” to “blame”, “hold responsible for”. You might think that vestiges of this early meaning still remain, considering the harm that wrongful blame can do!