Perilous, troublesome, distressful.

Dangerous.

Dangerous, hazardous, fraught with peril; causing or resulting in danger; risky. In early use also: spiritually dangerous.

Bad, in various senses (not always clearly distinguishable). Frequent in Middle English use; later… Difficult or dangerous; esp. of roads, passing…

Sinful; guilty.

Dangerous, perilous. Obsolete.

Perilous, dangerous, precarious; desperate, hazardous, dire. (Now the usual sense.)

Of events, affairs, conditions: Fraught or attended with evil or misfortune; having injurious or dangerous consequences; vexatious, irksome, hard…

Dangerous, perilous. Obsolete. rare.

Fraught with danger or risk; causing or occasioning danger; perilous, hazardous, risky, unsafe. (The current sense.)

= perilous, adj.

Full of danger, dangerous.

Fraught with danger.

figurative. Hard to get through or deal with; rough, rugged, difficult; perilous. Obsolete (except as directly figurative of preceding senses).

Full of peril; dangerous.

That endangers; dangerous.

Of ways or places: Dangerous from natural or other causes.

Perilous; dangerous (to someone or something).

Somewhat hazardous or perilous.

Of fighting, conflict, an onset: Vigorously conducted; pressing hard on or harassing the foe; also figurative. Of a combatant: Dangerous to…

Chiefly regional. Likely to break the neck; dangerous, hazardous. Cf. breakneck, adj. Now rare.

Unlucky, dangerous; also, eerie, uncanny.

Dangerous, unsafe.

Dangerous; not safe to meddle with.

colloquial. Chiefly British. Difficult to deal with or negotiate; dangerous.

Military slang. Dangerous.

Applied to a frightening or nerve-wracking place or situation. Services' slang.