Word blindness

Pops and I were working a code word puzzle in the evening standard. It's one where I was being a bit risky with putting in the letters (feeling like sometimes I had to try it in order to move forward). One of the cross checks could have been SHAM or WHAM, with the word WHIM/SHIM/WHOM/SHOM. We eventually decided it had to be WHOM - a word neither of us knew but were pronouncing WOM. Only on looking it up in the dictionary did we realise this is that commonly used word whom. 

whom

huːm/

pronoun

1. 1.

   used instead of ‘who’ as the object of a verb or preposition.

We laughed at ourselves. 

1.