What is the meaning of "Hip" in the given context?

I'm having difficulty interpreting the meaning of "Hip" even after consulting the dictionary.

Let me give the meanings given by the online Oxford dictionary:

hip 1 |hip|
noun
1. a projection of the pelvis and upper thigh bone on each side of the body in human beings and quadrupeds.
• ( hips) the circumference of the body at the buttocks : a sweater tied around the hips.
• a person's hip joint : she ran into a fence and dislocated her hip.
2. the sharp edge of a roof from the ridge to the eaves where two sides meet.

PHRASES
on the hip archaic: at a disadvantage.

ORIGIN
Old English hype, of Germanic origin; related to Dutch heup and German Hüfte.

hip 2 |hɪp| |hɪp| (also rose hip)
noun
the fruit of a rose, esp. a wild kind.

ORIGIN
Old English hēope, hīope; related to Dutch joop and German Hiefe.

hip 3 |hɪp| |hɪp|
adjective ( hipper |ˈhɪpər|, hippest |hɪp1st|) informal
following the latest fashion, esp. in popular music and clothes : it's becoming hip to be environmentally conscious.
• understanding; aware : he's trying to show how hip he is to Americana.

DERIVATIVES
hiply adverb
hipness |ˈhɪpn1s| noun
ORIGIN
early 20th cent.: of unknown origin.

hip 4 |hɪp| |hɪp|
exclamation
introducing a communal cheer : hip, hip, hooray!

ORIGIN mid 18th cent.: of unknown origin.

Now please consider the following sentence:

Ramu wore a T-shirt with a logo of his news paper and old pair of jeans. He looked unusually hip for someone in a crisis.

what does the hip imply here?

Solution 1:

This hip means cool or trendy.

Ramu wore a T-shirt with a logo of his newspaper and old pair of jeans. He looked unusually cool for someone in a crisis.

The preceding sentence describes Ramu's clothes. That would rule out hip¹ and hip², since we're talking about neither a pelvic bone nor part of a rose; however hip³ is related to fashion, "especially clothes". So, that old pair of jeans and T-shirt must have been especially fashionable or trendy.

Ergo: it's the third meaning in the definition you included:

adjective (hipper, hippest)
informal
following the latest fashion, especially in popular music and clothes:
it’s becoming hip to be environmentally conscious