ANSWER: Paul uses σάρξ (sarx), flesh, with four meanings, three of them in a good sense (1 Corinthians 15:39, Galatians 4:14, Galatians 2:16), and one in a bad sense, as in Romans 8:8, and generally in his epistles. But derivative adjective σαρκικός (sarkikos) and σάρκινος (sarkinos), carnal, is always used in a bad sense.
But Paul evidently uses it to express different degrees of evil tendency, the highest degree as in Romans 7, excluding spiritual life, "I am carnal, sold under sin," like a slave on the auction block bidden off, and completely controlled by sin. But in 1 Corinthians 3:1 the evil tendency is not controlling but controlled by divine grace, for the context proves that there is in them a low degree of spiritual life, for they are "in Crist," though "babes," and they are addressed as "Brethren." In the preceding chapter Paul describes two contrasted characters — the spiritual man and the natural of physical man. But when he attempts to classify the Corinthian believers he is puzzled. Strictly speaking, they are neither natural or unregenerate, nor spiritual or wholly sanctified; so he calls them carnal, evidently using the word not in its worst sense, excluding spiritual life. They were in the Galatian state in which "the flesh lusteth against the spirit," etc., Galatians 5:17, R.V. In Romans 7 the Holy Spirit is not named and the character delineated is an unregenerated person. The struggle is on the plane of nature. The combatants are the depraved animal nature warring against the moral reason. In the Galatian or Corinthian state they are not dead but on the way to the graveyard. "Having begun in the Spirit they are ending in the flesh."
— Steele's Answers pp. 21-23.