I'd like to suggest that if an expression is entered as a synonym with 'Identical meaning' checked, then a 2nd flag becomes available which, when checked, puts both expressions in an equivalence class sharing most properties but their spelling and a class of attributes specifically related to classifying/grouping spelling variants. If shared properties are already there, they need to be merged. If this cannot be handled safely by software (e.g. due to omissions or contradictions in preexisting data), the user must be prompted to solve them, or the flag cannot be set. The availability of options in this field might be subject to user preferences or privileges
• Purodha raised the priority of this task from to Needs Triage.