Answer:
The old man
Step-by-step explanation:
The old man according to apostle Paul in this epistle to the Ephesians is talking about our sinful nature. How that we have all sinned and come short of the glory of God, and that old man is the canal man who's been wallowing in sin.
Paul is admonishing the Ephesians here to do away with anything that has to do with their sinful nature now that they've been redeemed and become a new creature in God. This old body is easily corruptible and also prone to sin and therefore must be left in order to take up the new body in Christ which is incorruptible.