tough nut to crack
Stubborn problem indeed
A tough nut to crack is a person or problem that's difficult to understand, persuade, or solve.
The image is of a hard-shelled nut resisting efforts to open it: The new client is a tough nut to crack—she won't return my calls.
Also appears as hard nut to crack.
Something hard to fathom
- conundrumPerplexing problem or question
- riddlePuzzling question to solve
- mysterySomething unexplained or unknown
- brain-teaserChallenging mental puzzle
cipher · paradox · cryptic · perplexing · baffling · mystifying · inscrutable · unfathomable
Forced choice between undesirables
- quandaryState of perplexity
- predicamentDifficult, unpleasant situation
- impasseSituation without resolution
- stalemateMutual obstruction preventing progress
complication · bottleneck · barrier · roadblock · deadlock · standoff · logjam · gridlock
Refusing to change course
- guardedWary and restrained
- reservedRestrained in manner
- unyieldingRefusing to give way
- obstinateFirmly refusing to yield
secretive · defensive · closed-off · resistant · skeptic · holdout · hardliner · curmudgeon
Something blocking the way
- adversitySevere difficulty or suffering
- hardshipSuffering from difficult circumstances
- struggleLabored effort against resistance
- ordealDifficult, painful experience
difficulty · feat · undertaking · perseverance · determination · resilience · fortitude · tenacity
enigma
Something hard to fathom
- conundrumPerplexing problem or question
- riddlePuzzling question to solve
- mysterySomething unexplained or unknown
brain-teaser · cipher · paradox · cryptic · perplexing · baffling · mystifying · inscrutable · unfathomable · impenetrable
dilemma
Forced choice between undesirables
- quandaryState of perplexity
- predicamentDifficult, unpleasant situation
- impasseSituation without resolution
stalemate · complication · bottleneck · barrier · roadblock · deadlock · standoff · logjam · gridlock · snag
stubborn
Refusing to change course
- guardedWary and restrained
- reservedRestrained in manner
- unyieldingRefusing to give way
obstinate · secretive · defensive · closed-off · resistant · skeptic · holdout · hardliner · curmudgeon · stonewalling
obstacle
Something blocking the way
- adversitySevere difficulty or suffering
- hardshipSuffering from difficult circumstances
- struggleLabored effort against resistance
ordeal · difficulty · feat · undertaking · perseverance · determination · resilience · fortitude · tenacity · grit
tough nut to crackpiece of cake
Idiomatic easy task
easy as pie · no-brainer · child's play · cinch · cakewalk
tough nut to crackpushover
Easily defeated opponent
easy mark · soft touch · easy target · sucker · open book
tough, crack, toughness, toughen, tougher, toughie, toughest, toughened, nutcracker