abstruse

Từ điển LongMan Dictionary

ab‧struse/əbˈstruːs, æb-/ adjective formal
[date : 1500-1600; Language : Latin; Origin : past participle of abstrudere 'to hide', from abs- 'away' trudere 'to push']
unnecessarily complicated and difficult to understand:
　 ▪ Maths is a mix of abstruse theory and detailed calculations.

• Từ đồng nghĩa / Synonyms:
  deep, recondite