Final answer:
The word 'hazardous' functions as the objective complement in the sentence, modifying the direct object 'snakes' and completing the meaning of the sentence by describing the snakes as dangerous.
Step-by-step explanation:
The word in the sentence 'The hikers considered snakes hazardous' that functions as an objective complement is 'hazardous.' An objective complement is a word or group of words that follows and modifies the direct object and is necessary to complete the meaning of the sentence. In this case, 'snakes' is the direct object, and 'hazardous' is the objective complement because it describes the snakes as being dangerous, which is the opinion of the hikers.