needing a lot of skill or effort to do

困难的, 艰难的
needing a lot of work or skill to do, understand, or deal with

困难的, 艰难的
difficult to achieve or deal with

艰难的, 困难的
(of materials, courses, texts, etc.) complex and intended for individuals with prior knowledge or skill

高级的, 进阶的
having a level of knowledge or skill that is between beginner and advanced

中级的, 中等的
difficult to do or handle and requiring skill or caution

棘手的, 难处理的
requiring a lot of mental effort and hard work

艰巨的, 费力的
requiring great physical effort or energy

费力的, 艰苦的
(of a task) needing great effort, skill, etc.

艰巨的, 要求高的
difficult to accomplish, requiring skill or effort

具有挑战性的, 困难的
presenting difficulties or concerns, often requiring careful consideration or attention

有问题的, 成问题的
not exactly known or expressed, often leading to confusion or ambiguity

不明确, 模糊的
not clear or specific, lacking in detail or precision

模糊的, 不明确的
not easily defined or understood due to a lack of clarity or precision

模糊的, 不清晰的
difficult to comprehend due to being vague or hidden

晦涩的, 模糊的
unclear and not precisely stated or defined

模糊的, 含糊的
suggesting something without directly stating it

隐含的, 含蓄的
difficult to grasp mentally

难以捉摸的, 难以理解的
(of speech or written discourse) unclear or poorly organized in a way that is not comprehensible

不连贯的, 无条理的
difficult to understand or interpret

难以理解的, 神秘的
not clear or easily understood

令人困惑的, 难以理解的
causing confusion due to being complex or unclear

令人困惑的, 复杂难懂的
difficult to understand due to being complex or obscure

深奥的, 难解的
having mysterious and puzzling characteristics

神秘的, 难以理解的
vague and unclear, often used to describe ideas, concepts, or situations that are indistinct or hard to understand

模糊的, 不清晰的
difficult or impossible to comprehend or explain

神秘的, 不可知的
