gruelling

difficult

ˈdɪfɪk(ə)lt

adjective

needing much effort or skill to accomplish, deal with, or understand.

she had a difficult decision to make

hard,strenuous,arduous,laborious,heavy,tough,onerous,burdensome,demanding,punishing,gruelling,grinding,back-breaking,painful,exhausting,tiring,fatiguing,wearing,wearying,wearisome,hellish,killing,knackering,toilsome,exigent,problematic,puzzling,baffling,perplexing,confusing,mystifying,mysterious,complicated,complex,involved,intricate,knotty,thorny,ticklish,obscure,abstract,abstruse,recondite,enigmatic,impenetrable,unfathomable,over one’s head,above one’s head,beyond one,fiddly,sticky,no picnic,gnarly,wildering,involute,involuted

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demanding

dɪˈmɑːndɪŋ

adjective

(of a task) requiring much skill or effort.

she has a busy and demanding job

difficult,challenging,testing,taxing,exacting,tough,hard,onerous,burdensome,stressful,formidable,arduous,tiring,wearing,exhausting,wearying,wearisome,draining,uphill,rigorous,gruelling,back-breaking,Herculean,punishing,a tall order,knackering,toilsome

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challenging

ˈtʃalɪn(d)ʒɪŋ

adjective

testing one’s abilities; demanding.

challenging and rewarding employment

demanding,testing,taxing,exacting,exigent,searching,stretching,exciting,stimulating,inspiring,energizing,inspirational,difficult,tough,hard,heavy,stiff,formidable,onerous,arduous,laborious,burdensome,strenuous,gruelling

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burdensome

ˈbəːdns(ə)m

adjective

difficult to carry out or fulfil; taxing.

the burdensome responsibilities of professional life

onerous,oppressive,troublesome,weighty,worrisome,vexatious,irksome,trying,crushing,inconvenient,awkward,a nuisance,harsh,severe,stiff,stringent,formidable,an imposition,arduous,strenuous,rigorous,uphill,difficult,hard,laborious,Herculean,exhausting,tiring,taxing,demanding,punishing,gruelling,back-breaking,exacting,wearing,stressful,wearisome,fatiguing,toilsome,exigent

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backbreaking

adjective

(of manual labour) physically demanding.

a day’s back-breaking work

gruelling,arduous,strenuous,onerous,punishing,murderous,crushing,Herculean,demanding,exacting,taxing,formidable,exhausting,draining,laborious,burdensome,tough,stiff,uphill,heavy

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