All together and In the altogether

All together adverb - Used of a group whose members acted or were acted upon collectively and when `all' and `together' can be separated by other words.

In the altogether and all together are semantically related. In some cases you can use "In the altogether" instead an adjective phrase "All together".

In the altogether adjective - (used informally) completely unclothed.

All together and in the altogether are semantically related. Sometimes you can use "All together" instead an adjective phrase "In the altogether".