(m) means that a noun is masculine. Spanish nouns have a gender, which is either feminine (like la mujer or la luna) or masculine (like el hombre or el sol).
He's much too tenseDidn't it strike you that he was awfully uptight and tense?
her voice was tensese le notaba la tensión en la voz
He dropped gracelessly into a chair opposite her, his [expression] tense and angryTheir voices were subdued and their faces tense
to feel tensesentirse tenso
...a method you can use to relax yourself when you are feeling tenseRyle felt tired and tense
to get or grow tenseponerse tenso
They began to grow tense over the likelihood of a long delaySpeaking in public always makes him tense
2(stiff)[+body, muscles, neck]tenso;en tensión
She lay, eyes shut, [body] tense.Then his tense [body] relaxed into a posture of resignationYour [neck] is tensea bath can relax tense [muscles]...effective self-help techniques for relaxing tense [muscles] and easing pain
my shoulders are tensetengo los hombros tensos or en tensión
The [situation] in Baghdad remains tense.This gesture of goodwill did little to improve the tense [atmosphere] at the talkssounds like things are pretty tense over there...a day of tense [negotiations] between the International Red Cross and the Yugoslav federal army...India's most immediate neighbours, with whom [relations] have been tense in recent yearsthere was a tense [silence]. At length Jarvis sighed
[+period, moment]de tensión
There were a few tense moments before the presentation...the tense period of transition to an elected governmentAfter three very tense weeks he phoned again.
the tense situation in the Persian Gulfla situación de tensión en el golfo Pérsico
this is a [time] of tense relations between the two countries
4(taut)[+rope, wire]tenso;tirante
intransitive verb
(also tense up) [+person]ponerse tenso
He tensed as the other man gripped his shoulderShe tensed, but did not protestThe man on the terrace tensed slightly
[+muscle, body]ponerse tenso;ponerse en tensión
Her body tensed, involuntarilyGeorge's arm tensed underneath my fingersHer face tensed slightly as she told us how she had been forced to resignNewman's stomach [muscles] tensed
transitive verb
(also tense up) tensar;poner tenso
...the show-off in the gym tensing his stomach [muscles]Tense (up) the [muscles] in both of your legs.
she tensed her musclestensó or puso tensos los músculos