He is narrow-minded and won't take others' opinions.
Tips
usage
Mostly a bound morpheme. Common compounds: 险隘 ('strategic mountain pass'), 关隘 ('strategic pass / barrier'), 隘口 ('narrow pass'), 狭隘 ('narrow / narrow-minded'). 隘 alone is rare in modern prose.
memory
Left radical 阝 (the 'mound / hill' radical) appears in many topographic words: 险 ('perilous'), 阻 ('block'), 陡 ('steep'). Seeing 阝 on the left, expect terrain or geography.
On the left this is the mound radical (a contracted form of 阜), used for terrain features like cliffs and slopes. It marks 隘 as a landform - specifically the narrow defile between two hills - and groups it with 险, 陡 and 阴 in the topographic family.
Provides the sound, drifting noticeably from yì to ài along an Old Chinese pattern. The benefit meaning is unrelated to a narrow pass, but 益 efficiently carries the rhyme - readers familiar with 缢 or 溢 spot the same stem.