阻む

1. Origins, structure, and basic meaning

• Structure: 阻む (はばむ) is a transitive verb for blocking progress or realization. 阻んでいた is a continuing obstacle; 阻む原因 defines a hindering factor.
• Basic usage: A fallen tree keeps blocking hikers' path; insufficient funds become a cause preventing a plan's realization.

2. Common pitfalls and similar expressions

• Object blocking passage and condition preventing a plan
  • Object 行く手を is a physical route; 実現を is an abstract achievement. In both sentences the hindering cause takes が.