klättra

Swedish

klättra (present klättrar, preterite klättrade, supine klättrat, imperative klättra)

(transitive, intransitive) to climb (with hands and feet or the like)
klättra upp i ett träd
climb [up in] a tree

klättra upp på ett tak
climb onto [up on] a roof [less ambiguous than "up on" sounds since upp is a direction while uppe is a location]

klättra ner från taket
climb down from the roof

klättra upp för / uppför en bergssida
climb up a mountainside [the för can be thought of as along – intuitively, "klättra upp bergssidan" (incorrect) makes "klättra upp" sound like something done to the mountainside, like in "dress up"]

klättra ner för / nedför en bergssida
climb down a mountainside

klättra i träd
climb [in] trees [as an activity or the like]
(transitive, intransitive, by extension) to climb (along something, of something immobile)
Stigen klättrar brant uppför berget
The path climbs sharply up the mountain
(figuratively) to climb (advance)
klättra på karriärstegen
climb [on] the career ladder

To climb in the sense of rise (gain altitude (without gripping anything)) is to stiga.
Most idiomatic with a prepositional phrase when used transitively ("climb up / down / on / in / etc. something," rather than "climb something").
Stairs are never climbed in Swedish (unless on all fours or the like). "To climb the stairs" is to "gå upp för trappan" (walk up the stairs), or to "ta sig upp för trappan" (take oneself up the stairs) or the like if more effortful.
Turns into klätter- in compounds.

Conjugation of klättra (weak)

	Active		Passive
Infinitive	klättra		klättras
Supine	klättrat		klättrats
Imperative	klättra		—
Imper. plural¹	klättren		—
	Present	Past	Present	Past
Indicative	klättrar	klättrade	klättras	klättrades
Ind. plural¹	klättra	klättrade	klättras	klättrades
Subjunctive²	klättre	klättrade	klättres	klättrades
	Participles
Present participle	klättrande
Past participle	—
¹ Archaic. ² Dated. See the appendix on Swedish verbs.