Word Replacer

Hi,
I have a function which i use to replace words in a sentence.
The issue i am having is it is replacing a section of a word e.g. acknowledge the word know might be replaced with understand so we would be left with acunderstandledge which does not make sense.
The Mysql tabel is made up like this
Original work Replacements
know understand, be aware of
How do i change the function below so that it only replaces exact full word matches rather than i…
Word Replacer

See original post by adamjblakey