With the medical and social importance of resistant arterial hypertension (HTN) in mind, we had three goals in this paper: to study the definitions of resistant HTN in the guidelines on the topic, to analyze them, and to suggest some improvements. We found (at least) eleven insufficiencies in the definition of resistant HTN: (1) different blood pressure (BP) values are used for diagnoses; (2) the number of BP measurements is not specified; (3) the is not obtained; (4) it fails to provide or or BP values; (5) secondary HTN is not currently defined as true resistant HTN, but as apparently treatment-resistant HTN; (6) the definition usually directly incorporates BP cut-offs for systolic BP (sBP) and diastolic BP (dBP) making the diagnosis temporary; (7) in the exclusion strategy for resistant HTN; (8) there is potentially a need to introduce a category of resistant HTN; (9) to what to consider it as sufficient to change the diagnosis from "apparent treatment-resistant HTN" to the "resistant HTN"; (10) sBP values for 61 and 81 year old patients in some guidelines fulfill the criterion for resistant HTN; (11) it probably ought to read "In the absence of contraindications and compelling indications…" in the others. We believe that it is better to use the phrase "above the target BP" for the definition of (treatment) resistant HTN, because the whole story of resistant HTN is related to non-responders to antihypertensive treatment. Therefore, as we and not to normal values, it is appropriate to define resistant HTN as an insufficiency to reach the target BP values. Moreover, the definition of (treatment) resistant HTN should not be universal for every patient with HTN, but it should be age-related: (treatment) resistant HTN is elevated BP the target/normal BP values. Using this modification, there will be no need to automatically change the definition of resistant HTN when we change the BP targets in the future.