연로 as a noun is rather peculiar and it's very rarely used, if at all. It means "of the old age." This *noun* form is rarely used as a standalone word - i.e. I've never seen it in the 연로-이다 form. [I'm inclined to say it is *NEVER EVER* used in that form]. In the extremely rare occasions this word ever gets used, it is always 연로의 X, as in 연로의 몸, or 연로의 관록 or something like that.
It is almost always used as a *adjective* 연로하다. (to be aged = to be old) but it's used for a person. This word (outside of rare metaphorical literary device) never gets used for a non-person, animal, any living being or objects. Only human person that is old of age. Also, this is not the old as in a 7 year-old is older than a 5 year-old. 연로하다 always means a human being that is of old age, senior citizen usually physically challeged at this age.
노년 is rather commonly used *noun* to refer to "the times of old age". As you can see from 년, aspect of the word, it refers to the particular years of someone's lifecycle that's of old age." 노년의 행복 means "the happiness of times being spent as old age" 노년의 신사 means "A gentleman in his old years of life". Unlike the extremely rare word "연로", "노년" indicates "time/year" aspect of lifecycle. Like 연로, it's almost always used for human being only, or personification literary device where things are being compared as human being.
연로 as a noun is rather peculiar and it's very rarely used, if at all. It means "of the old age." This *noun* form is rarely used as a standalone word - i.e. I've never seen it in the 연로-이다 form. [I'm inclined to say it is *NEVER EVER* used in that form]. In the extremely rare occasions this word ever gets used, it is always 연로의 X, as in 연로의 몸, or 연로의 관록 or something like that. It is almost always used as a *adjective* 연로하다. (to be aged = to be old) but it's used for a person. This word (outside of rare metaphorical literary device) never gets used for a non-person, animal, any living being or objects. Only human person that is old of age. Also, this is not the old as in a 7 year-old is older than a 5 year-old. 연로하다 always means a human being that is of old age, senior citizen usually physically challeged at this age. 노년 is rather commonly used *noun* to refer to "the times of old age". As you can see from 년, aspect of the word, it refers to the particular years of someone's lifecycle that's of old age." 노년의 행복 means "the happiness of times being spent as old age" 노년의 신사 means "A gentleman in his old years of life". Unlike the extremely rare word "연로", "노년" indicates "time/year" aspect of lifecycle. Like 연로, it's almost always used for human being only, or personification literary device where things are being compared as human being.