5 Haraam Things
For ibadah, the term Haram and Halal is not appropriate. The best way to say it would be that Praying 5 times a day is obligatory on Muslims.
One can use these terms if one wants to (in loose terms), but the nature of this act is different and the linguistics of this also demand a different terminology to be used which is commensurate with the nature of act. 5 prayers are made obligatory on us, not made halal on us.
So can we say missing salah comes under ithm?