baffling

Từ điển WordNet v3.1 - WordNet Dictionary

adjective

making great mental demands;
hard to comprehend or solve or believe (Freq. 1)
- a baffling problem
- I faced the knotty problem of what to have for breakfast
- a problematic situation at home
• Syn:
elusive, knotty, problematic, problematical, tough
• Similar to:
difficult, hard
• Derivationally related forms:
toughness (for: tough), problem (for: problematical), problem (for: problematic), knottiness (for: knotty)