Achicarse – to back down, chicken out or choke in sports
Acobardarse – to chicken out
Apendejarse – to act like coward
Asustarse – to get frightened or scared
Asustado – scared
Asustante – scary (adjective)
Asustar – to scare
Aterrador – scary  (adjective)
Cagarse de miedo – to be scared shitless (vulgar)
Dar escalofríos – to gave someone the creeps
Dar miedo – run-of-the-mill fear For example: Me da miedo (It scares me)
Espantoso/horrible – For example: La muchacha se ve espantosa (The girl looks horrible/bad)
Espantapájaros – scarecrow
Espantasuegras – (thing for scaring off mother-in-laws) a rolled-up blow out party favor that you blow on and it unwinds
Espantar – to frighten
Espantarse   – to get scared
La casa de los espantos – a haunted house at an amusement park
Miedo – is a run-of-the-mill type of fear. For example: Tengo miedo de los perros (I’m afraid of dogs). Same as dar miedo.
Miedoso – scaredy cat
No tener agallas – to not have the guts to do something
No tener huevos – to not have balls or guts (vulgar)
No tener valor – means the same as the last two
Pavor – a phobia For example: Las serpientes me dan pavor (I am terrified of snakes)
Película de horror or película de miedo – a horror movie
Susto – is a sudden type of fear For example: ¡Qué susto! (What a scare!)
Temer – is a polite way to state fear. For example: Temo haber llegado en un mal momento (I fear I may arrived at a bad moment.)
Temer que – to fear that
Temblar de miedo – to be shaking with fear
Temor – a specific fear
Temor por – to fear for
Temoroso – fearful
Tener los huevos de corbata – (to have one’s testicles as a tie) to be fearful (vulgar)
Tener horror a algo – to be scared of something
Tener miedo a or tener miedo de – to be scared of For example: Tengo miedo de los perros or le tengo miedo a los perros (I am afraid of dogs)
Tenerle miedo a su propia sombra – to be scared of one’s own shadow

Tiquismos:

• Con mucho susto (with fear) is often used instead of con mucho gusto (you’re welcome). It is a play on words. There is another version. “Con mucho susto y poca gana”
• Espantar la mula – to leave or go
• Gato escaldado del agua fría huye – once bitten, twice shy
• Huevos tibios – a coward (vulgar)
• Pendejo – coward
• Gallina – chicken (coward)
• “No tiene nada que temer sino al temor mismo” – nothing to fear but fear itself FDR. I thought I’d throw this one in.