Re: RETURNS TABLE function: ERROR: column reference "word" is ambiguous

Given what you are doing, RETURN TABLE it will not work there for the same reason it does not work in 9.5:

https://www.postgresql.org/docs/9.6/static/plpgsql-control-structures.html#PLPGSQL-STATEMENTS-RETURNING

"If you declared the function with output parameters, write just RETURN NEXT with no expression. On each execution, the current values of the output parameter variable(s) will be saved for eventual return as a row of the result. Note that you must declare the function as returning SETOF record when there are multiple output parameters, or SETOF sometype when there is just one output parameter of type sometype, in order to create a set-returning function with output parameters."